diff --git a/CoqOfPython/CoqOfPython.v b/CoqOfPython/CoqOfPython.v
index b6128c3..4e197a9 100644
--- a/CoqOfPython/CoqOfPython.v
+++ b/CoqOfPython/CoqOfPython.v
@@ -8,13 +8,39 @@ From Hammer Require Export Tactics.
 
 Global Set Primitive Projections.
 Global Set Printing Projections.
-Global Open Scope list_scope.
 Global Open Scope string_scope.
-Global Open Scope Z_scope.
+Global Open Scope list_scope.
 Global Open Scope type_scope.
+Global Open Scope Z_scope.
 
 Export List.ListNotations.
 
+Inductive sigS {A : Type} (P : A -> Set) : Set :=
+| existS : forall (x : A), P x -> sigS P.
+Arguments existS {_ _}.
+
+Reserved Notation "{ x @ P }" (at level 0, x at level 99).
+Reserved Notation "{ x : A @ P }" (at level 0, x at level 99).
+Reserved Notation "{ ' pat : A @ P }"
+  (at level 0, pat strict pattern, format "{ ' pat : A @ P }").
+
+Notation "{ x @ P }" := (sigS (fun x => P)) : type_scope.
+Notation "{ x : A @ P }" := (sigS (A := A) (fun x => P)) : type_scope.
+Notation "{ ' pat : A @ P }" := (sigS (A := A) (fun pat => P)) : type_scope.
+
+Module Dict.
+  Definition t (Value : Set) : Set :=
+    list (string * Value).
+
+  Parameter read : forall {Value : Set}, t Value -> string -> option Value.
+
+  Parameter write : forall {Value : Set}, t Value -> string -> Value -> t Value.
+End Dict.
+
+Module Globals.
+  Definition t : Set := string.
+End Globals.
+
 Module Data.
   (** This type is not accessible directly in Python, as only object are. We use this type
       internally to represent integers, closures, ... that can be made accessible in a special
@@ -30,10 +56,10 @@ Module Data.
       a list when the number of elements is not statically known. *)
   | List (items : list Value)
   | Set_ (items : list Value)
-  | Dict (dict : list (string * Value))
+  | Dict (dict : Dict.t Value)
   | Closure {Value M : Set} (f : Value -> Value -> M)
   | Klass {Value M : Set}
-    (bases : list (string * string))
+    (bases : list (Globals.t * string))
     (class_methods : list (string * (Value -> Value -> M)))
     (methods : list (string * (Value -> Value -> M))).
   Arguments Ellipsis {_}.
@@ -52,11 +78,26 @@ End Data.
 Module Object.
   Record t {Value : Set} : Set := {
     internal : option (Data.t Value);
-    fields : list (string * Value);
+    fields : Dict.t Value;
   }.
   Arguments t : clear implicits.
   Arguments Build_t {_}.
 
+  Fixpoint fields_of_optional_dict {Value : Set} (optional_dict : list (string * option Value)) :
+      Dict.t Value :=
+    match optional_dict with
+    | [] => []
+    | (name, Some value) :: optional_dict =>
+      Dict.write (fields_of_optional_dict optional_dict) name value
+    | (_, None) :: optional_dict => fields_of_optional_dict optional_dict
+    end.
+
+  Definition make {Value : Set} (optional_dict : list (string * option Value)) : t Value :=
+    {|
+      internal := None;
+      fields := fields_of_optional_dict optional_dict;
+    |}.
+
   (** When an object is just a wrapper around the [Data.t] type. *)
   Definition wrapper {Value : Set} (data : Data.t Value) : t Value :=
     {|
@@ -66,41 +107,238 @@ Module Object.
 End Object.
 
 Module Pointer.
+  Module Mutable.
+    Inductive t (Value : Set) : Set :=
+    | Stack {A : Set} (index : nat) (to_object : A -> Object.t Value)
+    | Heap {Address A : Set} (address : Address) (to_object : A -> Object.t Value).
+    Arguments Stack {_ _}.
+    Arguments Heap {_ _ _}.
+  End Mutable.
+
   Inductive t (Value : Set) : Set :=
   | Imm (data : Object.t Value)
-  | Mutable {Address A : Set} (address : Address) (to_data : A -> Object.t Value).
+  | Mutable (mutable : Mutable.t Value).
   Arguments Imm {_}.
-  Arguments Mutable {_ _ _}.
+  Arguments Mutable {_}.
 End Pointer.
 
 Module Value.
   Inductive t : Set :=
-  | Make (globals : string) (klass : string) (value : Pointer.t t).
+  | Make (globals : Globals.t) (klass : string) (value : Pointer.t t).
 End Value.
 
-Parameter M : Set.
+Module Locals.
+  Definition t : Set := Pointer.t Value.t.
+End Locals.
+
+(** ** Constants *)
+Module Constant.
+  Definition None_ : Value.t :=
+    Value.Make "builtins" "NoneType" (Pointer.Imm {|
+      Object.internal := None;
+      Object.fields := [];
+    |}).
+
+  Definition ellipsis : Value.t :=
+    Value.Make "builtins" "ellipsis" (Pointer.Imm (Object.wrapper Data.Ellipsis)).
+
+  Definition bool (b : bool) : Value.t :=
+    Value.Make "builtins" "bool" (Pointer.Imm (Object.wrapper (Data.Bool b))).
+
+  Definition int (z : Z) : Value.t :=
+    Value.Make "builtins" "int" (Pointer.Imm (Object.wrapper (Data.Integer z))).
+
+  Definition float (f : string) : Value.t :=
+    Value.Make "builtins" "float" (Pointer.Imm (Object.wrapper (Data.Float f))).
+
+  Definition str (s : string) : Value.t :=
+    Value.Make "builtins" "str" (Pointer.Imm (Object.wrapper (Data.String s))).
+
+  Definition bytes (b : string) : Value.t :=
+    Value.Make "builtins" "bytes" (Pointer.Imm (Object.wrapper (Data.String b))).
+End Constant.
+
+Definition make_tuple (items : list Value.t) : Value.t :=
+  Value.Make "builtins" "tuple" (Pointer.Imm (Object.wrapper (Data.Tuple items))).
+
+Definition make_list (items : list Value.t) : Value.t :=
+  Value.Make "builtins" "list" (Pointer.Imm (Object.wrapper (Data.List items))).
+
+Definition make_set (items : list Value.t) : Value.t :=
+  Value.Make "builtins" "set" (Pointer.Imm (Object.wrapper (Data.Set_ items))).
+
+Parameter order_dict : list (string * Value.t) -> list (string * Value.t).
+
+Definition make_dict (dict : list (string * Value.t)) : Value.t :=
+  Value.Make "builtins" "dict" (Pointer.Imm (Object.wrapper (Data.Dict (order_dict dict)))).
+
+Module Primitive.
+  Inductive t : Set -> Set :=
+  | StateAlloc (object : Object.t Value.t) : t (Pointer.t Value.t)
+  | StateRead (mutable : Pointer.Mutable.t Value.t) : t (Object.t Value.t)
+  | StateWrite (mutable : Pointer.Mutable.t Value.t) (update : Object.t Value.t) : t unit
+  | GetInGlobals (globals : Globals.t) (name : string) : t Value.t.
+End Primitive.
+
+Module LowM.
+  Inductive t (A : Set) : Set :=
+  | Pure (a : A)
+  | CallPrimitive {B : Set} (primitive : Primitive.t B) (k : B -> t A)
+  | CallClosure {B : Set} (closure : Data.t Value.t) (args kwargs : Value.t) (k : B -> t A)
+  | Impossible.
+  Arguments Pure {_}.
+  Arguments CallPrimitive {_ _}.
+  Arguments CallClosure {_ _}.
+  Arguments Impossible {_}.
+
+  Fixpoint bind {A B : Set} (e1 : t A) (e2 : A -> t B) : t B :=
+    match e1 with
+    | Pure a => e2 a
+    | CallPrimitive primitive k => CallPrimitive primitive (fun v => bind (k v) e2)
+    | CallClosure closure args kwargs k => CallClosure closure args kwargs (fun a => bind (k a) e2)
+    | Impossible => Impossible
+    end.
+End LowM.
+
+Module Exception.
+  Inductive t : Set :=
+  | Return (value : Value.t)
+  | Continue
+  | Break
+  | Raise (value : option Value.t).
+End Exception.
+
+Definition M : Set :=
+  LowM.t (Value.t + Exception.t).
 
 Parameter IsInGlobals : string -> Value.t -> string -> Prop.
 
 Parameter IsImported : string -> string -> string -> Prop.
 
 Module M.
-  Parameter pure : Value.t -> M.
+  Definition pure (v : Value.t) : M :=
+    LowM.Pure (inl v).
+
+  Definition bind (e1 : M) (e2 : Value.t -> M) : M :=
+    LowM.bind e1 (fun v => match v with
+    | inl v => e2 v
+    | inr e => LowM.Pure (inr e)
+    end).
+
+  Definition impossible : M :=
+    LowM.Impossible.
+
+  (** This axiom is only used as a marker for the [monadic] tactic below, and should not appear in
+      the final code of the definitions once the tactic is applied. *)
+  Parameter run : M -> Value.t.
+
+  Module Notations.
+    Notation "'let-' a := b 'in' c" :=
+      (LowM.bind b (fun a => c))
+        (at level 200, b at level 100, a name).
+  
+    Notation "'let*' a := b 'in' c" :=
+      (bind b (fun a => c))
+        (at level 200, b at level 100, a name).
+  
+    Notation "'let*' ' a ':=' b 'in' c" :=
+      (bind b (fun a => c))
+      (at level 200, a pattern, b at level 100, c at level 200).
+
+    Notation "e (| e1 , .. , en |)" :=
+      (run ((.. (e e1) ..) en))
+      (at level 100).
 
-  Parameter let_ : M -> (Value.t -> M) -> M.
+    Notation "e (| |)" :=
+      (run e)
+      (at level 100).
+  End Notations.
+  Import Notations.
 
-  Parameter call : Value.t -> Value.t -> Value.t -> M.
+  Definition call_primitive {A : Set} (primitive : Primitive.t A) : LowM.t A :=
+    LowM.CallPrimitive primitive LowM.Pure.
+
+  Definition get_object (value : Value.t) : LowM.t (Object.t Value.t) :=
+    let 'Value.Make _ _ pointer := value in
+    match pointer with
+    | Pointer.Imm obj =>
+      LowM.Pure obj
+    | Pointer.Mutable mutable => call_primitive (Primitive.StateRead mutable)
+    end.
+
+  Definition call (f : Value.t) (args kwargs : Value.t) : M :=
+    let- f_object := get_object f in
+    match f_object.(Object.internal) with
+    | Some f => LowM.CallClosure f args kwargs LowM.Pure
+    | None => LowM.Impossible
+    end.
 
-  Parameter get_field : Value.t -> string -> M.
+  Definition get_field (value : Value.t) (field : string) : M :=
+    let- obj := get_object value in
+    match Dict.read obj.(Object.fields) field with
+    | Some value => pure value
+    | None => impossible
+    end.
 
   (** For the `x[i]` syntax. *)
-  Parameter get_subscript : Value.t -> Value.t -> M.
+  Definition get_subscript (value : Value.t) (key : Value.t) : M :=
+    let* __getitem__ := get_field value "__getitem__" in
+    call __getitem__ (make_tuple [key]) (make_dict []).
 
   Parameter slice : Value.t -> Value.t -> Value.t -> Value.t -> M.
 
-  Parameter get_name : string -> string -> M.
+  Definition read (pointer : Pointer.t Value.t) : LowM.t (Object.t Value.t) :=
+    match pointer with
+    | Pointer.Imm object => LowM.Pure object
+    | Pointer.Mutable mutable => call_primitive (Primitive.StateRead mutable)
+    end.
+
+  Fixpoint get_name_in_locals_stack
+      (locals_stack : list Locals.t)
+      (name : string) :
+      LowM.t (option Value.t) :=
+    match locals_stack with
+    | [] => LowM.Pure None
+    | locals :: locals_stack =>
+      let- locals_object := read locals in
+      match Dict.read locals_object.(Object.fields) name with
+      | Some value => LowM.Pure (Some value)
+      | None => get_name_in_locals_stack locals_stack name
+      end
+    end.
+
+  Definition get_name (globals : Globals.t) (locals_stack : list Locals.t) (name : string) : M :=
+    let- value_in_locals_stack := get_name_in_locals_stack locals_stack name in
+    match value_in_locals_stack with
+    | Some value => pure value
+    | None =>
+      let- value := call_primitive (Primitive.GetInGlobals globals name) in
+      pure value
+    end.
 
-  Parameter set_locals : Value.t -> Value.t -> list string -> M.
+  Fixpoint fields_of_args (args_values : list Value.t) (arg_names : list string) : Dict.t Value.t :=
+    match args_values, arg_names with
+    | value :: args_values, name :: arg_names =>
+      Dict.write (fields_of_args args_values arg_names) name value
+    | _, _ => []
+    end.
+
+  Definition create_locals
+      (locals_stack : list Locals.t)
+      (args kwargs : Value.t)
+      (arg_names : list string) :
+      LowM.t (list Locals.t) :=
+    let- args_object := get_object args in
+    let- args_values :=
+      match args_object.(Object.internal) with
+      | Some (Data.List arg_values) => LowM.Pure arg_values
+      | _ => LowM.Impossible
+      end in
+    let- new_locals := call_primitive (Primitive.StateAlloc {|
+      Object.internal := None;
+      Object.fields := fields_of_args args_values arg_names;
+    |}) in
+    LowM.Pure (new_locals :: locals_stack).
 
   Parameter assign : Value.t -> Value.t -> M.
 
@@ -124,33 +362,19 @@ Module M.
 
   Parameter assert : Value.t -> M.
 
-  Parameter impossible : M.
-
   Parameter if_then_else : Value.t -> M -> M -> M.
 
   Parameter for_ : Value.t -> Value.t -> M -> M -> M.
 
   Parameter while : Value.t -> M -> M -> M.
 
-  Parameter run : M -> Value.t.
-
-  Module Notations.
-    Notation "e (| e1 , .. , en |)" :=
-      (run ((.. (e e1) ..) en))
-      (at level 100).
-
-    Notation "e (| |)" :=
-      (run e)
-      (at level 100).
-  End Notations.
-
   (** A tactic that replaces all [M.run] markers with a bind operation.
       This allows to represent Rust programs without introducing
       explicit names for all intermediate computation results. *)
   Ltac monadic e :=
     lazymatch e with
     | context ctxt [let v : _ := ?x in @?f v] =>
-      refine (let_ _ _);
+      refine (bind _ _);
         [ monadic x
         | let v' := fresh v in
           intro v';
@@ -158,7 +382,7 @@ Module M.
           lazymatch context ctxt [let v := x in y] with
           | let _ := x in y => monadic y
           | _ =>
-            refine (let_ _ _);
+            refine (bind _ _);
               [ monadic y
               | let w := fresh "v" in
                 intro w;
@@ -171,7 +395,7 @@ Module M.
       lazymatch context ctxt [run x] with
       | run x => monadic x
       | _ =>
-        refine (let_ _ _);
+        refine (bind _ _);
           [ monadic x
           | let v := fresh "v" in
             intro v;
@@ -259,68 +483,26 @@ End Compare.
 
 (** ** Builtins *)
 Module builtins.
-  Definition globals : string := "builtins".
-
   Definition make_klass
     (bases : list (string * string))
     (class_methods : list (string * (Value.t -> Value.t -> M)))
     (methods : list (string * (Value.t -> Value.t -> M))) :
     Value.t :=
-  Value.Make builtins.globals "type" (Pointer.Imm (Object.wrapper (
+  Value.Make "builtins" "type" (Pointer.Imm (Object.wrapper (
     Data.Klass bases class_methods methods
   ))).
 
   Definition type : Value.t :=
     make_klass [] [] [].
-  Axiom type_in_globals : IsInGlobals globals type "type".
+  Axiom type_in_globals : IsInGlobals "builtins" type "type".
 
   Definition int : Value.t :=
     make_klass [] [] [].
-  Axiom int_in_globals : IsInGlobals globals int "int".
+  Axiom int_in_globals : IsInGlobals "builtins" int "int".
 
   Definition str : Value.t :=
     make_klass [] [] [].
-  Axiom str_in_globals : IsInGlobals globals str "str".
+  Axiom str_in_globals : IsInGlobals "builtins" str "str".
 End builtins.
 
-Module Constant.
-  Definition None_ : Value.t :=
-    Value.Make builtins.globals "NoneType" (Pointer.Imm {|
-      Object.internal := None;
-      Object.fields := [];
-    |}).
-
-  Definition ellipsis : Value.t :=
-    Value.Make builtins.globals "ellipsis" (Pointer.Imm (Object.wrapper Data.Ellipsis)).
-
-  Definition bool (b : bool) : Value.t :=
-    Value.Make builtins.globals "bool" (Pointer.Imm (Object.wrapper (Data.Bool b))).
-
-  Definition int (z : Z) : Value.t :=
-    Value.Make builtins.globals "int" (Pointer.Imm (Object.wrapper (Data.Integer z))).
-
-  Definition float (f : string) : Value.t :=
-    Value.Make builtins.globals "float" (Pointer.Imm (Object.wrapper (Data.Float f))).
-
-  Definition str (s : string) : Value.t :=
-    Value.Make builtins.globals "str" (Pointer.Imm (Object.wrapper (Data.String s))).
-
-  Definition bytes (b : string) : Value.t :=
-    Value.Make builtins.globals "bytes" (Pointer.Imm (Object.wrapper (Data.String b))).
-End Constant.
-
-Definition make_tuple (items : list Value.t) : Value.t :=
-  Value.Make builtins.globals "tuple" (Pointer.Imm (Object.wrapper (Data.Tuple items))).
-
-Definition make_list (items : list Value.t) : Value.t :=
-  Value.Make builtins.globals "list" (Pointer.Imm (Object.wrapper (Data.List items))).
-
 Parameter make_list_concat : list Value.t -> M.
-
-Definition make_set (items : list Value.t) : Value.t :=
-  Value.Make builtins.globals "set" (Pointer.Imm (Object.wrapper (Data.Set_ items))).
-
-Parameter order_dict : list (string * Value.t) -> list (string * Value.t).
-
-Definition make_dict (dict : list (string * Value.t)) : Value.t :=
-  Value.Make builtins.globals "dict" (Pointer.Imm (Object.wrapper (Data.Dict (order_dict dict)))).
diff --git a/CoqOfPython/ethereum/__init__.v b/CoqOfPython/ethereum/__init__.v
index e1c92c1..3994534 100644
--- a/CoqOfPython/ethereum/__init__.v
+++ b/CoqOfPython/ethereum/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.__init__".
+Definition globals : Globals.t := "ethereum.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,14 +39,14 @@ Definition EVM_RECURSION_LIMIT : Value.t := M.run ltac:(M.monadic (
 
 Definition expr_27 : Value.t :=
   M.call (|
-    M.get_field (| M.get_name (| globals, "sys" |), "setrecursionlimit" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "sys" |), "setrecursionlimit" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "EVM_RECURSION_LIMIT" |);
+          M.get_name (| globals, locals_stack, "EVM_RECURSION_LIMIT" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "sys" |), "getrecursionlimit" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "sys" |), "getrecursionlimit" |),
             make_list [],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/__init__.v b/CoqOfPython/ethereum/arrow_glacier/__init__.v
index 6adb453..70f81b6 100644
--- a/CoqOfPython/ethereum/arrow_glacier/__init__.v
+++ b/CoqOfPython/ethereum/arrow_glacier/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.__init__".
+Definition globals : Globals.t := "ethereum.arrow_glacier.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -13,7 +15,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 13773000
     ],
diff --git a/CoqOfPython/ethereum/arrow_glacier/blocks.v b/CoqOfPython/ethereum/arrow_glacier/blocks.v
index 09a6083..7e91936 100644
--- a/CoqOfPython/ethereum/arrow_glacier/blocks.v
+++ b/CoqOfPython/ethereum/arrow_glacier/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.blocks".
+Definition globals : Globals.t := "ethereum.arrow_glacier.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/arrow_glacier/bloom.v b/CoqOfPython/ethereum/arrow_glacier/bloom.v
index 9f27d32..128d38b 100644
--- a/CoqOfPython/ethereum/arrow_glacier/bloom.v
+++ b/CoqOfPython/ethereum/arrow_glacier/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.bloom".
+Definition globals : Globals.t := "ethereum.arrow_glacier.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_arrow_glacier_fork_types_imports_Bloom :
   IsImported globals "ethereum.arrow_glacier.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/fork.v b/CoqOfPython/ethereum/arrow_glacier/fork.v
index 00cdb50..c7458cf 100644
--- a/CoqOfPython/ethereum/arrow_glacier/fork.v
+++ b/CoqOfPython/ethereum/arrow_glacier/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.fork".
+Definition globals : Globals.t := "ethereum.arrow_glacier.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -150,7 +152,7 @@ Axiom ethereum_arrow_glacier_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -182,7 +184,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -200,10 +202,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -225,8 +227,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -246,13 +249,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -275,7 +279,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -286,9 +290,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -310,17 +314,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -333,13 +337,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -350,20 +354,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -388,112 +393,112 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -502,9 +507,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -513,9 +518,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -529,8 +534,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -553,22 +559,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -576,14 +582,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -592,40 +598,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -635,8 +641,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -645,36 +651,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -683,9 +689,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -693,8 +699,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -713,123 +720,123 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -838,28 +845,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -885,27 +893,27 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |);
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -913,8 +921,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -932,9 +941,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -942,25 +951,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -969,41 +978,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -1031,23 +1041,23 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1056,46 +1066,46 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -1104,38 +1114,39 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -1159,7 +1170,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -1168,10 +1179,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1181,9 +1192,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1196,10 +1207,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1209,9 +1220,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1221,7 +1232,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.return_ (|
-              M.get_name (| globals, "receipt" |)
+              M.get_name (| globals, locals_stack, "receipt" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -1240,8 +1251,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1286,22 +1298,22 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1310,16 +1322,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1327,9 +1339,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1337,14 +1349,14 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1352,18 +1364,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1371,49 +1383,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1422,56 +1434,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1482,8 +1494,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1508,27 +1521,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1537,9 +1550,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1557,46 +1570,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1607,19 +1620,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1628,23 +1641,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1652,16 +1665,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1675,13 +1688,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1696,11 +1709,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1708,88 +1721,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1802,8 +1815,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1832,44 +1846,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1881,19 +1895,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1906,8 +1920,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1935,30 +1950,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1967,10 +1982,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
@@ -1979,8 +1994,8 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1989,100 +2004,100 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "effective_gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "effective_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2090,7 +2105,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2099,10 +2114,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2110,25 +2125,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -2152,14 +2167,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2167,10 +2182,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2178,20 +2193,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -2200,17 +2215,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2218,41 +2233,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -2260,31 +2275,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -2295,20 +2310,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -2321,14 +2336,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2340,27 +2355,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2376,13 +2391,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -2411,17 +2427,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -2436,8 +2452,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2466,14 +2483,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2481,7 +2498,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2489,7 +2506,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2503,9 +2520,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2516,7 +2533,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2535,10 +2552,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2546,26 +2563,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2581,17 +2598,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2600,8 +2617,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2624,47 +2642,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2672,10 +2690,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2683,19 +2701,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2705,18 +2723,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2728,58 +2746,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2796,10 +2814,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2808,15 +2826,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2831,10 +2849,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2843,15 +2861,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2870,13 +2888,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2891,8 +2909,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2908,12 +2927,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2924,8 +2943,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2943,19 +2963,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2971,8 +2991,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2988,14 +3009,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3007,8 +3028,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -3024,14 +3046,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3043,8 +3065,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -3078,12 +3101,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -3094,8 +3117,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -3126,18 +3150,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3154,10 +3178,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3174,8 +3198,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -3193,8 +3217,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -3238,21 +3263,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -3262,11 +3287,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -3284,13 +3309,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -3299,13 +3324,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -3316,7 +3341,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -3326,7 +3351,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -3336,13 +3361,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/fork_types.v b/CoqOfPython/ethereum/arrow_glacier/fork_types.v
index e46e8cb..d1223e7 100644
--- a/CoqOfPython/ethereum/arrow_glacier/fork_types.v
+++ b/CoqOfPython/ethereum/arrow_glacier/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.fork_types".
+Definition globals : Globals.t := "ethereum.arrow_glacier.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/arrow_glacier/state.v b/CoqOfPython/ethereum/arrow_glacier/state.v
index 455bfaa..a0b8e6e 100644
--- a/CoqOfPython/ethereum/arrow_glacier/state.v
+++ b/CoqOfPython/ethereum/arrow_glacier/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.state".
+Definition globals : Globals.t := "ethereum.arrow_glacier.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/transactions.v b/CoqOfPython/ethereum/arrow_glacier/transactions.v
index 67ba8e4..ab24a7f 100644
--- a/CoqOfPython/ethereum/arrow_glacier/transactions.v
+++ b/CoqOfPython/ethereum/arrow_glacier/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.transactions".
+Definition globals : Globals.t := "ethereum.arrow_glacier.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,14 +99,15 @@ Definition FeeMarketTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -112,17 +115,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -131,10 +134,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -144,9 +147,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -159,10 +162,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -172,9 +175,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -184,7 +187,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "Exception" |),
+                  M.get_name (| globals, locals_stack, "Exception" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -199,8 +202,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -208,10 +212,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -222,7 +226,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -231,11 +235,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -252,7 +256,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -261,11 +265,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -277,7 +281,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
-                let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                 M.pure Constant.None_
               )) |) in
             M.pure Constant.None_
@@ -286,7 +290,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/arrow_glacier/trie.v b/CoqOfPython/ethereum/arrow_glacier/trie.v
index 0941ddc..a607f38 100644
--- a/CoqOfPython/ethereum/arrow_glacier/trie.v
+++ b/CoqOfPython/ethereum/arrow_glacier/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.trie".
+Definition globals : Globals.t := "ethereum.arrow_glacier.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_arrow_glacier_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,34 +124,34 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -187,14 +189,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -218,7 +221,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -234,10 +237,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -246,13 +249,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -261,10 +264,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -273,13 +276,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -288,10 +291,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -300,9 +303,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -310,7 +313,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -327,9 +330,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -339,9 +342,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -350,16 +353,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -369,8 +372,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -380,25 +384,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -410,10 +414,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -421,13 +425,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -442,27 +446,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -486,8 +490,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -504,14 +509,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -522,8 +527,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -543,8 +549,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -552,14 +558,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -571,18 +577,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -602,10 +609,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -613,21 +620,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -640,11 +648,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -652,12 +660,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -665,7 +673,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -680,9 +688,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -690,8 +698,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -728,7 +737,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -739,9 +748,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -752,13 +761,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -766,15 +775,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -784,20 +793,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -815,7 +824,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -823,13 +832,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -838,15 +847,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -856,20 +865,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -887,9 +896,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -897,8 +906,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -915,14 +925,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -933,26 +943,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -960,17 +970,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -982,9 +992,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -992,8 +1002,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1014,9 +1025,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1025,25 +1036,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1051,13 +1062,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1071,9 +1082,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1081,13 +1092,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1095,15 +1106,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1113,22 +1124,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1137,13 +1148,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1164,10 +1176,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1175,14 +1187,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1200,12 +1212,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1218,12 +1230,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1235,18 +1247,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1256,8 +1268,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1281,9 +1294,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1302,12 +1315,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1320,9 +1333,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1333,24 +1346,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1360,8 +1373,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1369,31 +1382,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1408,7 +1421,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1429,7 +1442,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1437,30 +1450,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1480,9 +1493,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1490,7 +1503,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1508,21 +1521,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1530,19 +1543,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1551,8 +1564,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1561,17 +1574,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1584,10 +1597,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/utils/__init__.v b/CoqOfPython/ethereum/arrow_glacier/utils/__init__.v
index 15ee17f..67b99d9 100644
--- a/CoqOfPython/ethereum/arrow_glacier/utils/__init__.v
+++ b/CoqOfPython/ethereum/arrow_glacier/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.utils.__init__".
+Definition globals : Globals.t := "ethereum.arrow_glacier.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/arrow_glacier/utils/address.v b/CoqOfPython/ethereum/arrow_glacier/utils/address.v
index 34dfc3f..a702f3e 100644
--- a/CoqOfPython/ethereum/arrow_glacier/utils/address.v
+++ b/CoqOfPython/ethereum/arrow_glacier/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.utils.address".
+Definition globals : Globals.t := "ethereum.arrow_glacier.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_arrow_glacier_fork_types_imports_Address :
   IsImported globals "ethereum.arrow_glacier.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/utils/hexadecimal.v b/CoqOfPython/ethereum/arrow_glacier/utils/hexadecimal.v
index 7d39659..ff8431f 100644
--- a/CoqOfPython/ethereum/arrow_glacier/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/arrow_glacier/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.arrow_glacier.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_arrow_glacier_fork_types_imports_Root :
   IsImported globals "ethereum.arrow_glacier.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/arrow_glacier/utils/message.v b/CoqOfPython/ethereum/arrow_glacier/utils/message.v
index c8a6555..f3cf69e 100644
--- a/CoqOfPython/ethereum/arrow_glacier/utils/message.v
+++ b/CoqOfPython/ethereum/arrow_glacier/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.utils.message".
+Definition globals : Globals.t := "ethereum.arrow_glacier.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_arrow_glacier_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.arrow_glacier.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/__init__.v b/CoqOfPython/ethereum/arrow_glacier/vm/__init__.v
index 19418af..07ef173 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/__init__.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.__init__".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/exceptions.v b/CoqOfPython/ethereum/arrow_glacier/vm/exceptions.v
index c699641..ed3e40a 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/exceptions.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.exceptions".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/gas.v b/CoqOfPython/ethereum/arrow_glacier/vm/gas.v
index ca2cac0..49e4e06 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/gas.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.gas".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_arrow_glacier_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -326,7 +328,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -336,7 +338,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -356,7 +358,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -376,7 +378,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -406,7 +408,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -416,7 +418,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -426,7 +428,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -465,8 +467,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -479,13 +482,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -496,22 +499,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -521,8 +524,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -542,9 +546,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -554,15 +558,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -571,16 +575,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,12 +624,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -634,14 +639,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -655,9 +660,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -665,20 +670,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -691,8 +696,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -706,16 +711,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -723,9 +728,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -734,13 +739,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -750,10 +755,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -761,8 +766,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -793,13 +799,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -807,32 +813,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -846,18 +852,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -868,15 +874,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -885,8 +891,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -902,9 +909,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/__init__.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/__init__.v
index 2163ec5..1309d4b 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/arithmetic.v
index 9c026ce..9597ba5 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/bitwise.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/bitwise.v
index db4eddd..c847f7a 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/block.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/block.v
index b5df822..1a1ef12 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/comparison.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/comparison.v
index a48a324..908a3d2 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/control_flow.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/control_flow.v
index ab3b78d..5ddb601 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/environment.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/environment.v
index 182c5e4..df5ed9f 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,42 +1472,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1500,21 +1520,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1523,7 +1543,7 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/keccak.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/keccak.v
index eea02f8..1f22c7b 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/log.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/log.v
index 77cb339..2011aea 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_pop :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/memory.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/memory.v
index 4fdbe0d..2b19411 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/stack.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/stack.v
index ba06637..6b754e3 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_arrow_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.arrow_glacier.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/storage.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/storage.v
index b104e43..04a8c7a 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/system.v b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/system.v
index 315f8d0..642da72 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,28 +107,29 @@ Axiom ethereum_arrow_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.arrow_glacier.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -136,32 +139,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -171,15 +174,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -195,10 +198,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -208,15 +211,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -237,29 +240,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -279,27 +282,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -307,10 +310,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -318,27 +321,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -351,25 +354,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -381,8 +384,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -394,9 +398,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -404,9 +408,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -414,9 +418,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -424,46 +428,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -472,26 +476,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -506,9 +511,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -516,9 +521,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -526,9 +531,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -537,9 +542,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -550,11 +555,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -564,12 +569,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -580,43 +585,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -625,26 +630,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -656,9 +662,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -666,9 +672,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -676,63 +682,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -740,24 +747,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -777,11 +784,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -789,10 +796,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -800,7 +807,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -808,10 +815,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -819,27 +826,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -852,23 +859,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -882,16 +889,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -903,14 +910,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -919,8 +926,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -932,12 +940,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -948,12 +956,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -964,9 +972,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -974,9 +982,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -984,9 +992,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -994,9 +1002,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1004,9 +1012,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1014,12 +1022,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1029,28 +1037,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1060,16 +1068,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1077,7 +1085,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1085,7 +1093,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1093,13 +1101,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1107,56 +1115,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1165,25 +1173,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1192,17 +1200,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1212,32 +1220,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1245,14 +1253,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1264,12 +1273,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1280,12 +1289,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1296,9 +1305,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,9 +1335,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1336,26 +1345,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1365,28 +1374,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1395,13 +1404,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1409,58 +1418,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1469,17 +1478,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1489,32 +1498,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1522,14 +1531,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1541,12 +1551,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1556,28 +1566,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1589,20 +1599,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1615,7 +1625,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1623,32 +1633,32 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1656,33 +1666,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1692,9 +1702,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1702,19 +1712,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1724,15 +1734,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1744,12 +1755,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1760,12 +1771,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1776,9 +1787,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1786,9 +1797,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1796,9 +1807,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1806,9 +1817,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1816,12 +1827,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1831,104 +1842,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1940,12 +1952,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1956,12 +1968,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1972,9 +1984,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1982,9 +1994,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1992,9 +2004,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2002,9 +2014,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2012,12 +2024,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2027,110 +2039,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2142,9 +2155,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2152,9 +2165,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2162,54 +2175,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/interpreter.v b/CoqOfPython/ethereum/arrow_glacier/vm/interpreter.v
index 7958dd7..c82ea50 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/interpreter.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.interpreter".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -126,7 +128,7 @@ Axiom ethereum_arrow_glacier_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -149,8 +151,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -172,9 +175,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -186,10 +189,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -197,44 +200,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -248,10 +251,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -264,10 +267,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -276,13 +279,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -292,12 +295,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -314,14 +317,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -329,7 +332,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -337,7 +340,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -349,22 +352,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -374,29 +377,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -404,8 +407,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -422,43 +426,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -466,24 +470,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -491,22 +495,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -526,13 +531,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -544,17 +549,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -562,10 +567,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -573,12 +578,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -590,10 +595,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -601,13 +606,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -615,22 +620,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -648,14 +654,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -663,13 +669,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/memory.v b/CoqOfPython/ethereum/arrow_glacier/vm/memory.v
index 207f7fb..4e18aa3 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/memory.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.memory".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/__init__.v
index 2d091ab..51c0478 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/alt_bn128.v
index 4649b5a..401bbbb 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_arrow_glacier_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.arrow_glacier.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/blake2f.v
index 0cad2c6..1c0b95b 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_arrow_glacier_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.arrow_glacier.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ecrecover.v
index aaa3942..287fab3 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_arrow_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.arrow_glacier.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/identity.v
index 7443148..5934829 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_arrow_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.arrow_glacier.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/mapping.v
index d47d1fc..a762493 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/modexp.v
index df32505..9fae72b 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ripemd160.v
index cc2bc0a..bdaeafd 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_arrow_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.arrow_glacier.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/sha256.v
index ce66ace..d0c1ce0 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_arrow_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.arrow_glacier.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/runtime.v b/CoqOfPython/ethereum/arrow_glacier/vm/runtime.v
index 4e59678..b2c3715 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/runtime.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.runtime".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_arrow_glacier_vm_instructions_imports_Ops :
   IsImported globals "ethereum.arrow_glacier.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/arrow_glacier/vm/stack.v b/CoqOfPython/ethereum/arrow_glacier/vm/stack.v
index 9258f93..815fc8e 100644
--- a/CoqOfPython/ethereum/arrow_glacier/vm/stack.v
+++ b/CoqOfPython/ethereum/arrow_glacier/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.arrow_glacier.vm.stack".
+Definition globals : Globals.t := "ethereum.arrow_glacier.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_arrow_glacier_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.arrow_glacier.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/base_types.v b/CoqOfPython/ethereum/base_types.v
index 4229846..bf2b870 100644
--- a/CoqOfPython/ethereum/base_types.v
+++ b/CoqOfPython/ethereum/base_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.base_types".
+Definition globals : Globals.t := "ethereum.base_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -95,20 +97,21 @@ Definition Uint : Value.t :=
     [
       (
         "from_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into an arbitrarily sized unsigned integer
         from its big endian representation.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "big"
                   ],
                   make_dict []
@@ -121,20 +124,21 @@ Definition Uint : Value.t :=
       );
       (
         "from_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into an arbitrarily sized unsigned integer
         from its little endian representation.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "little"
                   ],
                   make_dict []
@@ -149,23 +153,24 @@ Definition Uint : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "value" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "value" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "TypeError" |),
+                M.get_name (| globals, locals_stack, "TypeError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -178,13 +183,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "value" |),
+                M.get_name (| globals, locals_stack, "value" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -197,13 +202,14 @@ Definition Uint : Value.t :=
       );
       (
         "__radd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -212,23 +218,24 @@ Definition Uint : Value.t :=
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -239,13 +246,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -256,14 +263,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__add__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__add__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -275,13 +282,14 @@ Definition Uint : Value.t :=
       );
       (
         "__iadd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -290,23 +298,24 @@ Definition Uint : Value.t :=
       );
       (
         "__sub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -318,20 +327,20 @@ Definition Uint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.lt (|
-                    M.get_name (| globals, "self" |),
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |),
+                    M.get_name (| globals, locals_stack, "right" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -342,14 +351,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__sub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__sub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -361,23 +370,24 @@ Definition Uint : Value.t :=
       );
       (
         "__rsub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -389,20 +399,20 @@ Definition Uint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "self" |),
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |),
+                    M.get_name (| globals, locals_stack, "left" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -413,14 +423,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rsub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rsub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -432,13 +442,14 @@ Definition Uint : Value.t :=
       );
       (
         "__isub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__sub__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__sub__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -447,23 +458,24 @@ Definition Uint : Value.t :=
       );
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -474,13 +486,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -491,14 +503,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__mul__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mul__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -510,13 +522,14 @@ Definition Uint : Value.t :=
       );
       (
         "__rmul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -525,13 +538,14 @@ Definition Uint : Value.t :=
       );
       (
         "__imul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -540,23 +554,24 @@ Definition Uint : Value.t :=
       );
       (
         "__floordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -567,13 +582,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -584,14 +599,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__floordiv__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__floordiv__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -603,23 +618,24 @@ Definition Uint : Value.t :=
       );
       (
         "__rfloordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -630,13 +646,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "left" |),
+                M.get_name (| globals, locals_stack, "left" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -647,14 +663,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rfloordiv__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rfloordiv__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -666,13 +682,14 @@ Definition Uint : Value.t :=
       );
       (
         "__ifloordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__floordiv__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__floordiv__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -681,23 +698,24 @@ Definition Uint : Value.t :=
       );
       (
         "__mod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -708,13 +726,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -725,14 +743,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__mod__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mod__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -744,23 +762,24 @@ Definition Uint : Value.t :=
       );
       (
         "__rmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -771,13 +790,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "left" |),
+                M.get_name (| globals, locals_stack, "left" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -788,14 +807,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rmod__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rmod__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -807,13 +826,14 @@ Definition Uint : Value.t :=
       );
       (
         "__imod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mod__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mod__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -822,23 +842,24 @@ Definition Uint : Value.t :=
       );
       (
         "__divmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -849,13 +870,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -867,31 +888,31 @@ Definition Uint : Value.t :=
           let _ := M.assign_local (|
             "result" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__divmod__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__divmod__" |),
               make_list [
-                M.get_name (| globals, "self" |);
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "self" |);
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.return_ (|
             make_tuple [ M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 0
                 |)
               ],
               make_dict []
             |); M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 1
                 |)
               ],
@@ -902,23 +923,24 @@ Definition Uint : Value.t :=
       );
       (
         "__rdivmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -929,13 +951,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "left" |),
+                M.get_name (| globals, locals_stack, "left" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -947,31 +969,31 @@ Definition Uint : Value.t :=
           let _ := M.assign_local (|
             "result" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__rdivmod__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rdivmod__" |),
               make_list [
-                M.get_name (| globals, "self" |);
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "self" |);
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.return_ (|
             make_tuple [ M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 0
                 |)
               ],
               make_dict []
             |); M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 1
                 |)
               ],
@@ -982,13 +1004,14 @@ Definition Uint : Value.t :=
       );
       (
         "__pow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right"; "modulo" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.is_not (|
-                M.get_name (| globals, "modulo" |),
+                M.get_name (| globals, locals_stack, "modulo" |),
                 Constant.None_
               |),
             (* then *)
@@ -997,17 +1020,17 @@ Definition Uint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   UnOp.not (| M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "modulo" |);
-                      M.get_name (| globals, "int" |)
+                      M.get_name (| globals, locals_stack, "modulo" |);
+                      M.get_name (| globals, locals_stack, "int" |)
                     ],
                     make_dict []
                   |) |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
-                    M.get_name (| globals, "NotImplemented" |)
+                    M.get_name (| globals, locals_stack, "NotImplemented" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -1018,13 +1041,13 @@ Definition Uint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   Compare.lt (|
-                    M.get_name (| globals, "modulo" |),
+                    M.get_name (| globals, locals_stack, "modulo" |),
                     Constant.int 0
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.raise (| Some (M.call (|
-                    M.get_name (| globals, "OverflowError" |),
+                    M.get_name (| globals, locals_stack, "OverflowError" |),
                     make_list [],
                     make_dict []
                   |)) |) in
@@ -1042,17 +1065,17 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1063,13 +1086,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1080,15 +1103,15 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__pow__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__pow__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |);
-                    M.get_name (| globals, "modulo" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |);
+                    M.get_name (| globals, locals_stack, "modulo" |)
                   ],
                   make_dict []
                 |)
@@ -1100,13 +1123,14 @@ Definition Uint : Value.t :=
       );
       (
         "__rpow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left"; "modulo" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.is_not (|
-                M.get_name (| globals, "modulo" |),
+                M.get_name (| globals, locals_stack, "modulo" |),
                 Constant.None_
               |),
             (* then *)
@@ -1115,17 +1139,17 @@ Definition Uint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   UnOp.not (| M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "modulo" |);
-                      M.get_name (| globals, "int" |)
+                      M.get_name (| globals, locals_stack, "modulo" |);
+                      M.get_name (| globals, locals_stack, "int" |)
                     ],
                     make_dict []
                   |) |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
-                    M.get_name (| globals, "NotImplemented" |)
+                    M.get_name (| globals, locals_stack, "NotImplemented" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -1136,13 +1160,13 @@ Definition Uint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   Compare.lt (|
-                    M.get_name (| globals, "modulo" |),
+                    M.get_name (| globals, locals_stack, "modulo" |),
                     Constant.int 0
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.raise (| Some (M.call (|
-                    M.get_name (| globals, "OverflowError" |),
+                    M.get_name (| globals, locals_stack, "OverflowError" |),
                     make_list [],
                     make_dict []
                   |)) |) in
@@ -1160,17 +1184,17 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1181,13 +1205,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "left" |),
+                M.get_name (| globals, locals_stack, "left" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1198,15 +1222,15 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rpow__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rpow__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |);
-                    M.get_name (| globals, "modulo" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |);
+                    M.get_name (| globals, locals_stack, "modulo" |)
                   ],
                   make_dict []
                 |)
@@ -1218,14 +1242,15 @@ Definition Uint : Value.t :=
       );
       (
         "__ipow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right"; "modulo" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__pow__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__pow__" |),
               make_list [
-                M.get_name (| globals, "right" |);
-                M.get_name (| globals, "modulo" |)
+                M.get_name (| globals, locals_stack, "right" |);
+                M.get_name (| globals, locals_stack, "modulo" |)
               ],
               make_dict []
             |)
@@ -1234,23 +1259,24 @@ Definition Uint : Value.t :=
       );
       (
         "__xor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1261,13 +1287,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "right" |),
+                M.get_name (| globals, locals_stack, "right" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1278,14 +1304,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__xor__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__xor__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -1297,23 +1323,24 @@ Definition Uint : Value.t :=
       );
       (
         "__rxor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1324,13 +1351,13 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "left" |),
+                M.get_name (| globals, locals_stack, "left" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1341,14 +1368,14 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rxor__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rxor__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -1360,13 +1387,14 @@ Definition Uint : Value.t :=
       );
       (
         "__ixor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__xor__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__xor__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -1375,18 +1403,19 @@ Definition Uint : Value.t :=
       );
       (
         "to_be_bytes32",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this arbitrarily sized unsigned integer into its big endian
         representation with exactly 32 bytes.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "Bytes32" |),
+              M.get_name (| globals, locals_stack, "Bytes32" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
                   make_list [
                     Constant.int 32;
                     Constant.str "big"
@@ -1401,8 +1430,9 @@ Definition Uint : Value.t :=
       );
       (
         "to_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this arbitrarily sized unsigned integer into its big endian
         representation, without padding.
@@ -1410,7 +1440,7 @@ Definition Uint : Value.t :=
           let _ := M.assign_local (|
             "bit_length" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
               make_list [],
               make_dict []
             |)
@@ -1419,7 +1449,7 @@ Definition Uint : Value.t :=
             "byte_length" ,
             BinOp.floor_div (|
               BinOp.add (|
-                M.get_name (| globals, "bit_length" |),
+                M.get_name (| globals, locals_stack, "bit_length" |),
                 Constant.int 7
               |),
               Constant.int 8
@@ -1427,9 +1457,9 @@ Definition Uint : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
               make_list [
-                M.get_name (| globals, "byte_length" |);
+                M.get_name (| globals, locals_stack, "byte_length" |);
                 Constant.str "big"
               ],
               make_dict []
@@ -1439,8 +1469,9 @@ Definition Uint : Value.t :=
       );
       (
         "to_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "number_bytes" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "number_bytes" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this arbitrarily sized unsigned integer into its little endian
         representation, without padding.
@@ -1449,7 +1480,7 @@ Definition Uint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.is (|
-                M.get_name (| globals, "number_bytes" |),
+                M.get_name (| globals, locals_stack, "number_bytes" |),
                 Constant.None_
               |),
             (* then *)
@@ -1457,7 +1488,7 @@ Definition Uint : Value.t :=
               let _ := M.assign_local (|
                 "bit_length" ,
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
                   make_list [],
                   make_dict []
                 |)
@@ -1466,7 +1497,7 @@ Definition Uint : Value.t :=
                 "number_bytes" ,
                 BinOp.floor_div (|
                   BinOp.add (|
-                    M.get_name (| globals, "bit_length" |),
+                    M.get_name (| globals, locals_stack, "bit_length" |),
                     Constant.int 7
                   |),
                   Constant.int 8
@@ -1479,9 +1510,9 @@ Definition Uint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
               make_list [
-                M.get_name (| globals, "number_bytes" |);
+                M.get_name (| globals, locals_stack, "number_bytes" |);
                 Constant.str "little"
               ],
               make_dict []
@@ -1493,7 +1524,7 @@ Definition Uint : Value.t :=
 
 Definition T : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "T"
     ],
@@ -1510,23 +1541,24 @@ Definition FixedUint : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "value" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "value" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "TypeError" |),
+                M.get_name (| globals, locals_stack, "TypeError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1540,20 +1572,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "value" |),
+                  M.get_name (| globals, locals_stack, "value" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "value" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "value" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1566,13 +1598,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__radd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -1581,23 +1614,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1607,10 +1641,10 @@ Definition FixedUint : Value.t :=
           let _ := M.assign_local (|
             "result" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "self" |);
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "self" |);
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -1620,20 +1654,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "result" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "result" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1644,10 +1678,10 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
-                M.get_name (| globals, "result" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
+                M.get_name (| globals, locals_stack, "result" |)
               ],
               make_dict []
             |)
@@ -1656,8 +1690,9 @@ Definition FixedUint : Value.t :=
       );
       (
         "wrapping_add",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Return a new instance containing `self + right (mod N)`.
 
@@ -1671,17 +1706,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1693,20 +1728,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1717,19 +1752,19 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 BinOp.bit_and (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "int" |), "__add__" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__add__" |),
                     make_list [
-                      M.get_name (| globals, "self" |);
-                      M.get_name (| globals, "right" |)
+                      M.get_name (| globals, locals_stack, "self" |);
+                      M.get_name (| globals, locals_stack, "right" |)
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -1739,13 +1774,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__iadd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -1754,23 +1790,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__sub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1782,19 +1819,19 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   BoolOp.or (|
                     Compare.gt (|
-                      M.get_name (| globals, "right" |),
-                      M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                      M.get_name (| globals, locals_stack, "right" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt (|
-                        M.get_name (| globals, "self" |),
-                        M.get_name (| globals, "right" |)
+                        M.get_name (| globals, locals_stack, "self" |),
+                        M.get_name (| globals, locals_stack, "right" |)
                       |)
                     ))
                   |)
@@ -1803,7 +1840,7 @@ Definition FixedUint : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1814,14 +1851,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__sub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__sub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -1833,8 +1870,9 @@ Definition FixedUint : Value.t :=
       );
       (
         "wrapping_sub",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Return a new instance containing `self - right (mod N)`.
 
@@ -1848,17 +1886,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1870,20 +1908,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1894,19 +1932,19 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 BinOp.bit_and (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "int" |), "__sub__" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__sub__" |),
                     make_list [
-                      M.get_name (| globals, "self" |);
-                      M.get_name (| globals, "right" |)
+                      M.get_name (| globals, locals_stack, "self" |);
+                      M.get_name (| globals, locals_stack, "right" |)
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -1916,23 +1954,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rsub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1944,19 +1983,19 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   BoolOp.or (|
                     Compare.gt (|
-                      M.get_name (| globals, "left" |),
-                      M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                      M.get_name (| globals, locals_stack, "left" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                     |),
                     ltac:(M.monadic (
                       Compare.gt (|
-                        M.get_name (| globals, "self" |),
-                        M.get_name (| globals, "left" |)
+                        M.get_name (| globals, locals_stack, "self" |),
+                        M.get_name (| globals, locals_stack, "left" |)
                       |)
                     ))
                   |)
@@ -1965,7 +2004,7 @@ Definition FixedUint : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -1976,14 +2015,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rsub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rsub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -1995,13 +2034,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__isub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__sub__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__sub__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2010,23 +2050,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2036,10 +2077,10 @@ Definition FixedUint : Value.t :=
           let _ := M.assign_local (|
             "result" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "self" |);
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "self" |);
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2049,20 +2090,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "result" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "result" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2073,10 +2114,10 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
-                M.get_name (| globals, "result" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
+                M.get_name (| globals, locals_stack, "result" |)
               ],
               make_dict []
             |)
@@ -2085,8 +2126,9 @@ Definition FixedUint : Value.t :=
       );
       (
         "wrapping_mul",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Return a new instance containing `self * right (mod N)`.
 
@@ -2100,17 +2142,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2122,20 +2164,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2146,19 +2188,19 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 BinOp.bit_and (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "int" |), "__mul__" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mul__" |),
                     make_list [
-                      M.get_name (| globals, "self" |);
-                      M.get_name (| globals, "right" |)
+                      M.get_name (| globals, locals_stack, "self" |);
+                      M.get_name (| globals, locals_stack, "right" |)
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -2168,13 +2210,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rmul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -2183,13 +2226,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__imul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2198,23 +2242,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__floordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2226,20 +2271,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2250,14 +2295,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__floordiv__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__floordiv__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -2269,23 +2314,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rfloordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2297,20 +2343,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "left" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "left" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2321,14 +2367,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rfloordiv__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rfloordiv__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -2340,13 +2386,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__ifloordiv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__floordiv__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__floordiv__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2355,23 +2402,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__mod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2383,20 +2431,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2407,14 +2455,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__mod__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mod__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -2426,23 +2474,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2454,20 +2503,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "left" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "left" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2478,14 +2527,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rmod__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rmod__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -2497,13 +2546,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__imod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mod__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mod__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2512,23 +2562,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__divmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2540,20 +2591,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2566,36 +2617,36 @@ Definition FixedUint : Value.t :=
             "result" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "super" |),
+                M.get_name (| globals, locals_stack, "super" |),
                 make_list [
-                  M.get_name (| globals, "FixedUint" |);
-                  M.get_name (| globals, "self" |)
+                  M.get_name (| globals, locals_stack, "FixedUint" |);
+                  M.get_name (| globals, locals_stack, "self" |)
                 ],
                 make_dict []
               |), "__divmod__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.return_ (|
             make_tuple [ M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 0
                 |)
               ],
               make_dict []
             |); M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 1
                 |)
               ],
@@ -2606,23 +2657,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rdivmod__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2634,20 +2686,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "left" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "left" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2660,36 +2712,36 @@ Definition FixedUint : Value.t :=
             "result" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "super" |),
+                M.get_name (| globals, locals_stack, "super" |),
                 make_list [
-                  M.get_name (| globals, "FixedUint" |);
-                  M.get_name (| globals, "self" |)
+                  M.get_name (| globals, locals_stack, "FixedUint" |);
+                  M.get_name (| globals, locals_stack, "self" |)
                 ],
                 make_dict []
               |), "__rdivmod__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.return_ (|
             make_tuple [ M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 0
                 |)
               ],
               make_dict []
             |); M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.get_subscript (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   Constant.int 1
                 |)
               ],
@@ -2700,13 +2752,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__pow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right"; "modulo" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.is_not (|
-                M.get_name (| globals, "modulo" |),
+                M.get_name (| globals, locals_stack, "modulo" |),
                 Constant.None_
               |),
             (* then *)
@@ -2715,17 +2768,17 @@ Definition FixedUint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   UnOp.not (| M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "modulo" |);
-                      M.get_name (| globals, "int" |)
+                      M.get_name (| globals, locals_stack, "modulo" |);
+                      M.get_name (| globals, locals_stack, "int" |)
                     ],
                     make_dict []
                   |) |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
-                    M.get_name (| globals, "NotImplemented" |)
+                    M.get_name (| globals, locals_stack, "NotImplemented" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -2737,20 +2790,20 @@ Definition FixedUint : Value.t :=
                 M.if_then_else (|
                   BoolOp.or (|
                     Compare.lt (|
-                      M.get_name (| globals, "modulo" |),
+                      M.get_name (| globals, locals_stack, "modulo" |),
                       Constant.int 0
                     |),
                     ltac:(M.monadic (
                       Compare.gt (|
-                        M.get_name (| globals, "modulo" |),
-                        M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                        M.get_name (| globals, locals_stack, "modulo" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                       |)
                     ))
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.raise (| Some (M.call (|
-                    M.get_name (| globals, "OverflowError" |),
+                    M.get_name (| globals, locals_stack, "OverflowError" |),
                     make_list [],
                     make_dict []
                   |)) |) in
@@ -2768,17 +2821,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2788,11 +2841,11 @@ Definition FixedUint : Value.t :=
           let _ := M.assign_local (|
             "result" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__pow__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__pow__" |),
               make_list [
-                M.get_name (| globals, "self" |);
-                M.get_name (| globals, "right" |);
-                M.get_name (| globals, "modulo" |)
+                M.get_name (| globals, locals_stack, "self" |);
+                M.get_name (| globals, locals_stack, "right" |);
+                M.get_name (| globals, locals_stack, "modulo" |)
               ],
               make_dict []
             |)
@@ -2802,19 +2855,19 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   BoolOp.or (|
                     Compare.gt (|
-                      M.get_name (| globals, "right" |),
-                      M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                      M.get_name (| globals, locals_stack, "right" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                     |),
                     ltac:(M.monadic (
                       Compare.gt (|
-                        M.get_name (| globals, "result" |),
-                        M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                        M.get_name (| globals, locals_stack, "result" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                       |)
                     ))
                   |)
@@ -2823,7 +2876,7 @@ Definition FixedUint : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2834,10 +2887,10 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
-                M.get_name (| globals, "result" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
+                M.get_name (| globals, locals_stack, "result" |)
               ],
               make_dict []
             |)
@@ -2846,8 +2899,9 @@ Definition FixedUint : Value.t :=
       );
       (
         "wrapping_pow",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right"; "modulo" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Return a new instance containing `self ** right (mod modulo)`.
 
@@ -2863,7 +2917,7 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.is_not (|
-                M.get_name (| globals, "modulo" |),
+                M.get_name (| globals, locals_stack, "modulo" |),
                 Constant.None_
               |),
             (* then *)
@@ -2872,17 +2926,17 @@ Definition FixedUint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   UnOp.not (| M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "modulo" |);
-                      M.get_name (| globals, "int" |)
+                      M.get_name (| globals, locals_stack, "modulo" |);
+                      M.get_name (| globals, locals_stack, "int" |)
                     ],
                     make_dict []
                   |) |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
-                    M.get_name (| globals, "NotImplemented" |)
+                    M.get_name (| globals, locals_stack, "NotImplemented" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -2894,20 +2948,20 @@ Definition FixedUint : Value.t :=
                 M.if_then_else (|
                   BoolOp.or (|
                     Compare.lt (|
-                      M.get_name (| globals, "modulo" |),
+                      M.get_name (| globals, locals_stack, "modulo" |),
                       Constant.int 0
                     |),
                     ltac:(M.monadic (
                       Compare.gt (|
-                        M.get_name (| globals, "modulo" |),
-                        M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                        M.get_name (| globals, locals_stack, "modulo" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                       |)
                     ))
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.raise (| Some (M.call (|
-                    M.get_name (| globals, "OverflowError" |),
+                    M.get_name (| globals, locals_stack, "OverflowError" |),
                     make_list [],
                     make_dict []
                   |)) |) in
@@ -2925,17 +2979,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2947,20 +3001,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -2971,20 +3025,20 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 BinOp.bit_and (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "int" |), "__pow__" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__pow__" |),
                     make_list [
-                      M.get_name (| globals, "self" |);
-                      M.get_name (| globals, "right" |);
-                      M.get_name (| globals, "modulo" |)
+                      M.get_name (| globals, locals_stack, "self" |);
+                      M.get_name (| globals, locals_stack, "right" |);
+                      M.get_name (| globals, locals_stack, "modulo" |)
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -2994,13 +3048,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rpow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left"; "modulo" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.is_not (|
-                M.get_name (| globals, "modulo" |),
+                M.get_name (| globals, locals_stack, "modulo" |),
                 Constant.None_
               |),
             (* then *)
@@ -3009,17 +3064,17 @@ Definition FixedUint : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   UnOp.not (| M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "modulo" |);
-                      M.get_name (| globals, "int" |)
+                      M.get_name (| globals, locals_stack, "modulo" |);
+                      M.get_name (| globals, locals_stack, "int" |)
                     ],
                     make_dict []
                   |) |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
-                    M.get_name (| globals, "NotImplemented" |)
+                    M.get_name (| globals, locals_stack, "NotImplemented" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -3031,20 +3086,20 @@ Definition FixedUint : Value.t :=
                 M.if_then_else (|
                   BoolOp.or (|
                     Compare.lt (|
-                      M.get_name (| globals, "modulo" |),
+                      M.get_name (| globals, locals_stack, "modulo" |),
                       Constant.int 0
                     |),
                     ltac:(M.monadic (
                       Compare.gt (|
-                        M.get_name (| globals, "modulo" |),
-                        M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                        M.get_name (| globals, locals_stack, "modulo" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                       |)
                     ))
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.raise (| Some (M.call (|
-                    M.get_name (| globals, "OverflowError" |),
+                    M.get_name (| globals, locals_stack, "OverflowError" |),
                     make_list [],
                     make_dict []
                   |)) |) in
@@ -3062,17 +3117,17 @@ Definition FixedUint : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3084,20 +3139,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "left" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "left" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3108,15 +3163,15 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rpow__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rpow__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |);
-                    M.get_name (| globals, "modulo" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |);
+                    M.get_name (| globals, locals_stack, "modulo" |)
                   ],
                   make_dict []
                 |)
@@ -3128,14 +3183,15 @@ Definition FixedUint : Value.t :=
       );
       (
         "__ipow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right"; "modulo" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right"; "modulo" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__pow__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__pow__" |),
               make_list [
-                M.get_name (| globals, "right" |);
-                M.get_name (| globals, "modulo" |)
+                M.get_name (| globals, locals_stack, "right" |);
+                M.get_name (| globals, locals_stack, "modulo" |)
               ],
               make_dict []
             |)
@@ -3144,23 +3200,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__and__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3172,20 +3229,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3196,14 +3253,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__and__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__and__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -3215,23 +3272,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__or__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3243,20 +3301,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3267,14 +3325,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__or__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__or__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -3286,23 +3344,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__xor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3314,20 +3373,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "right" |),
+                  M.get_name (| globals, locals_stack, "right" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "right" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "right" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3338,14 +3397,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__xor__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__xor__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -3357,23 +3416,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rxor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3385,20 +3445,20 @@ Definition FixedUint : Value.t :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.lt (|
-                  M.get_name (| globals, "left" |),
+                  M.get_name (| globals, locals_stack, "left" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.gt (|
-                    M.get_name (| globals, "left" |),
-                    M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                    M.get_name (| globals, locals_stack, "left" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "OverflowError" |),
+                M.get_name (| globals, locals_stack, "OverflowError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3409,14 +3469,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rxor__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rxor__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -3428,13 +3488,14 @@ Definition FixedUint : Value.t :=
       );
       (
         "__ixor__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__xor__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__xor__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -3443,22 +3504,23 @@ Definition FixedUint : Value.t :=
       );
       (
         "__invert__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 BinOp.bit_and (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "int" |), "__invert__" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__invert__" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "MAX_VALUE" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -3468,23 +3530,24 @@ Definition FixedUint : Value.t :=
       );
       (
         "__rshift__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "shift_by" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "shift_by" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "shift_by" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "shift_by" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -3493,14 +3556,14 @@ Definition FixedUint : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "__class__" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__class__" |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rshift__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rshift__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "shift_by" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "shift_by" |)
                   ],
                   make_dict []
                 |)
@@ -3512,8 +3575,9 @@ Definition FixedUint : Value.t :=
       );
       (
         "to_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this unsigned integer into its big endian representation,
         omitting leading zero bytes.
@@ -3521,7 +3585,7 @@ Definition FixedUint : Value.t :=
           let _ := M.assign_local (|
             "bit_length" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
               make_list [],
               make_dict []
             |)
@@ -3530,7 +3594,7 @@ Definition FixedUint : Value.t :=
             "byte_length" ,
             BinOp.floor_div (|
               BinOp.add (|
-                M.get_name (| globals, "bit_length" |),
+                M.get_name (| globals, locals_stack, "bit_length" |),
                 Constant.int 7
               |),
               Constant.int 8
@@ -3538,9 +3602,9 @@ Definition FixedUint : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
               make_list [
-                M.get_name (| globals, "byte_length" |);
+                M.get_name (| globals, locals_stack, "byte_length" |);
                 Constant.str "big"
               ],
               make_dict []
@@ -3556,8 +3620,9 @@ Definition U256 : Value.t :=
     [
       (
         "from_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into a fixed sized unsigned integer
         from its big endian representation.
@@ -3567,9 +3632,9 @@ Definition U256 : Value.t :=
             M.if_then_else (|
               Compare.gt (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |)
+                    M.get_name (| globals, locals_stack, "buffer" |)
                   ],
                   make_dict []
                 |),
@@ -3578,7 +3643,7 @@ Definition U256 : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3589,12 +3654,12 @@ Definition U256 : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "big"
                   ],
                   make_dict []
@@ -3607,8 +3672,9 @@ Definition U256 : Value.t :=
       );
       (
         "from_signed",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "value" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "value" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Creates an unsigned integer representing `value` using two's
         complement.
@@ -3617,16 +3683,16 @@ Definition U256 : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "value" |),
+                M.get_name (| globals, locals_stack, "value" |),
                 Constant.int 0
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
                 M.call (|
-                  M.get_name (| globals, "cls" |),
+                  M.get_name (| globals, locals_stack, "cls" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -3638,11 +3704,11 @@ Definition U256 : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 BinOp.bit_and (|
-                  M.get_name (| globals, "value" |),
-                  M.get_field (| M.get_name (| globals, "cls" |), "MAX_VALUE" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MAX_VALUE" |)
                 |)
               ],
               make_dict []
@@ -3654,18 +3720,19 @@ Definition U256 : Value.t :=
     [
       (
         "to_be_bytes32",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this 256-bit unsigned integer into its big endian
         representation with exactly 32 bytes.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "Bytes32" |),
+              M.get_name (| globals, locals_stack, "Bytes32" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
                   make_list [
                     Constant.int 32;
                     Constant.str "big"
@@ -3680,8 +3747,9 @@ Definition U256 : Value.t :=
       );
       (
         "to_signed",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Decodes a signed integer from its two's complement representation.
         " in
@@ -3690,7 +3758,7 @@ Definition U256 : Value.t :=
             M.if_then_else (|
               Compare.lt (|
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
                   make_list [],
                   make_dict []
                 |),
@@ -3700,9 +3768,9 @@ Definition U256 : Value.t :=
             ltac:(M.monadic (
               let _ := M.return_ (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |)
@@ -3715,13 +3783,13 @@ Definition U256 : Value.t :=
           let _ := M.return_ (|
             BinOp.sub (|
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "self" |)
+                  M.get_name (| globals, locals_stack, "self" |)
                 ],
                 make_dict []
               |),
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             |)
           |) in
           M.pure Constant.None_))
@@ -3736,8 +3804,9 @@ Definition U32 : Value.t :=
     [
       (
         "from_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into an arbitrarily sized unsigned integer
         from its little endian representation.
@@ -3747,9 +3816,9 @@ Definition U32 : Value.t :=
             M.if_then_else (|
               Compare.gt (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |)
+                    M.get_name (| globals, locals_stack, "buffer" |)
                   ],
                   make_dict []
                 |),
@@ -3758,7 +3827,7 @@ Definition U32 : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3769,12 +3838,12 @@ Definition U32 : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "little"
                   ],
                   make_dict []
@@ -3789,18 +3858,19 @@ Definition U32 : Value.t :=
     [
       (
         "to_le_bytes4",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this fixed sized unsigned integer into its little endian
         representation, with exactly 4 bytes.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "Bytes4" |),
+              M.get_name (| globals, locals_stack, "Bytes4" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
                   make_list [
                     Constant.int 4;
                     Constant.str "little"
@@ -3815,8 +3885,9 @@ Definition U32 : Value.t :=
       );
       (
         "to_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this fixed sized unsigned integer into its little endian
         representation, in the fewest bytes possible.
@@ -3824,7 +3895,7 @@ Definition U32 : Value.t :=
           let _ := M.assign_local (|
             "bit_length" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
               make_list [],
               make_dict []
             |)
@@ -3833,7 +3904,7 @@ Definition U32 : Value.t :=
             "byte_length" ,
             BinOp.floor_div (|
               BinOp.add (|
-                M.get_name (| globals, "bit_length" |),
+                M.get_name (| globals, locals_stack, "bit_length" |),
                 Constant.int 7
               |),
               Constant.int 8
@@ -3841,9 +3912,9 @@ Definition U32 : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
               make_list [
-                M.get_name (| globals, "byte_length" |);
+                M.get_name (| globals, locals_stack, "byte_length" |);
                 Constant.str "little"
               ],
               make_dict []
@@ -3861,8 +3932,9 @@ Definition U64 : Value.t :=
     [
       (
         "from_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into an arbitrarily sized unsigned integer
         from its little endian representation.
@@ -3872,9 +3944,9 @@ Definition U64 : Value.t :=
             M.if_then_else (|
               Compare.gt (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |)
+                    M.get_name (| globals, locals_stack, "buffer" |)
                   ],
                   make_dict []
                 |),
@@ -3883,7 +3955,7 @@ Definition U64 : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3894,12 +3966,12 @@ Definition U64 : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "little"
                   ],
                   make_dict []
@@ -3912,8 +3984,9 @@ Definition U64 : Value.t :=
       );
       (
         "from_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into an unsigned 64 bit integer from its
         big endian representation.
@@ -3923,9 +3996,9 @@ Definition U64 : Value.t :=
             M.if_then_else (|
               Compare.gt (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |)
+                    M.get_name (| globals, locals_stack, "buffer" |)
                   ],
                   make_dict []
                 |),
@@ -3934,7 +4007,7 @@ Definition U64 : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [],
                 make_dict []
               |)) |) in
@@ -3945,12 +4018,12 @@ Definition U64 : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "big"
                   ],
                   make_dict []
@@ -3965,18 +4038,19 @@ Definition U64 : Value.t :=
     [
       (
         "to_le_bytes8",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this fixed sized unsigned integer into its little endian
         representation, with exactly 8 bytes.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "Bytes8" |),
+              M.get_name (| globals, locals_stack, "Bytes8" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
                   make_list [
                     Constant.int 8;
                     Constant.str "little"
@@ -3991,8 +4065,9 @@ Definition U64 : Value.t :=
       );
       (
         "to_le_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this fixed sized unsigned integer into its little endian
         representation, in the fewest bytes possible.
@@ -4000,7 +4075,7 @@ Definition U64 : Value.t :=
           let _ := M.assign_local (|
             "bit_length" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "bit_length" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "bit_length" |),
               make_list [],
               make_dict []
             |)
@@ -4009,7 +4084,7 @@ Definition U64 : Value.t :=
             "byte_length" ,
             BinOp.floor_div (|
               BinOp.add (|
-                M.get_name (| globals, "bit_length" |),
+                M.get_name (| globals, locals_stack, "bit_length" |),
                 Constant.int 7
               |),
               Constant.int 8
@@ -4017,9 +4092,9 @@ Definition U64 : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
               make_list [
-                M.get_name (| globals, "byte_length" |);
+                M.get_name (| globals, locals_stack, "byte_length" |);
                 Constant.str "little"
               ],
               make_dict []
@@ -4033,7 +4108,7 @@ Definition U64 : Value.t :=
 
 Definition B : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "B"
     ],
@@ -4050,8 +4125,9 @@ Definition FixedBytes : Value.t :=
     [
       (
         "__new__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Create a new instance, ensuring the result has the correct length.
         " in
@@ -4059,18 +4135,18 @@ Definition FixedBytes : Value.t :=
             "result" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "super" |),
+                M.get_name (| globals, locals_stack, "super" |),
                 make_list [
-                  M.get_name (| globals, "FixedBytes" |);
-                  M.get_name (| globals, "cls" |)
+                  M.get_name (| globals, locals_stack, "FixedBytes" |);
+                  M.get_name (| globals, locals_stack, "cls" |)
                 ],
                 make_dict []
               |), "__new__" |),
               make_list_concat (| [
                 make_list [
-                  M.get_name (| globals, "cls" |)
+                  M.get_name (| globals, locals_stack, "cls" |)
                 ];
-                M.get_name (| globals, "args" |)
+                M.get_name (| globals, locals_stack, "args" |)
               ] |),
               make_dict []
             |)
@@ -4080,18 +4156,18 @@ Definition FixedBytes : Value.t :=
             M.if_then_else (|
               Compare.not_eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "result" |)
+                    M.get_name (| globals, locals_stack, "result" |)
                   ],
                   make_dict []
                 |),
-                M.get_field (| M.get_name (| globals, "cls" |), "LENGTH" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "LENGTH" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [
                   Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                 ],
@@ -4103,7 +4179,7 @@ Definition FixedBytes : Value.t :=
               M.pure Constant.None_
             )) |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           |) in
           M.pure Constant.None_))
       )
@@ -4190,7 +4266,7 @@ Definition Bytes256 : Value.t :=
     ].
 
 Definition Bytes : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "bytes" |)
+  M.get_name (| globals, locals_stack, "bytes" |)
 )).
 
 Definition expr_925 : Value.t :=
@@ -4199,15 +4275,16 @@ Sequence of bytes (octets) of arbitrary length.
 ".
 
 Definition _setattr_function : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "self"; "attr"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "attr"; "value" ] in
+    ltac:(M.monadic (
     let _ :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "getattr" |),
+          M.get_name (| globals, locals_stack, "getattr" |),
           make_list [
-            M.get_name (| globals, "self" |);
+            M.get_name (| globals, locals_stack, "self" |);
             Constant.str "_frozen";
             Constant.None_
           ],
@@ -4216,7 +4293,7 @@ Definition _setattr_function : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "Exception" |),
+          M.get_name (| globals, locals_stack, "Exception" |),
           make_list [
             Constant.str "Mutating frozen dataclasses is not allowed."
           ],
@@ -4226,11 +4303,11 @@ Definition _setattr_function : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "object" |), "__setattr__" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "object" |), "__setattr__" |),
     make_list [
-      M.get_name (| globals, "self" |);
-      M.get_name (| globals, "attr" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "self" |);
+      M.get_name (| globals, locals_stack, "attr" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -4239,16 +4316,17 @@ Definition _setattr_function : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _delattr_function : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "self"; "attr" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "attr" ] in
+    ltac:(M.monadic (
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "self" |), "_frozen" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_frozen" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "Exception" |),
+          M.get_name (| globals, locals_stack, "Exception" |),
           make_list [
             Constant.str "Mutating frozen dataclasses is not allowed."
           ],
@@ -4258,10 +4336,10 @@ Definition _delattr_function : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "object" |), "__delattr__" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "object" |), "__delattr__" |),
     make_list [
-      M.get_name (| globals, "self" |);
-      M.get_name (| globals, "attr" |)
+      M.get_name (| globals, locals_stack, "self" |);
+      M.get_name (| globals, locals_stack, "attr" |)
     ],
     make_dict []
   |) in
@@ -4270,17 +4348,19 @@ Definition _delattr_function : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _make_init_function : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "f" ] in
+    ltac:(M.monadic (
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
-      M.get_name (| globals, "init_function" |)
+      M.get_name (| globals, locals_stack, "init_function" |)
     |) in
     M.pure Constant.None_)).
 
 Definition slotted_freezable : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Monkey patches a dataclass so it can be frozen by setting `_frozen` to
     `True` and uses `__slots__` for efficiency.
@@ -4289,52 +4369,52 @@ Definition slotted_freezable : Value.t -> Value.t -> M :=
     to `__init__`.
     " in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "cls" |), "__slots__" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__slots__" |),
       BinOp.add (|
         make_tuple [ Constant.str "_frozen" ],
         M.call (|
-          M.get_name (| globals, "tuple" |),
+          M.get_name (| globals, locals_stack, "tuple" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "cls" |), "__annotations__" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__annotations__" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "cls" |), "__init__" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__init__" |),
       M.call (|
-        M.get_name (| globals, "_make_init_function" |),
+        M.get_name (| globals, locals_stack, "_make_init_function" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "cls" |), "__init__" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__init__" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "cls" |), "__setattr__" |),
-      M.get_name (| globals, "_setattr_function" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__setattr__" |),
+      M.get_name (| globals, locals_stack, "_setattr_function" |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "cls" |), "__delattr__" |),
-      M.get_name (| globals, "_delattr_function" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__delattr__" |),
+      M.get_name (| globals, locals_stack, "_delattr_function" |)
     |) in
     let _ := M.return_ (|
       M.call (|
         M.call (|
-          M.get_name (| globals, "type" |),
+          M.get_name (| globals, locals_stack, "type" |),
           make_list [
-            M.get_name (| globals, "cls" |)
+            M.get_name (| globals, locals_stack, "cls" |)
           ],
           make_dict []
         |),
         make_list [
-          M.get_field (| M.get_name (| globals, "cls" |), "__name__" |);
-          M.get_field (| M.get_name (| globals, "cls" |), "__bases__" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__name__" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__bases__" |);
           M.call (|
-            M.get_name (| globals, "dict" |),
+            M.get_name (| globals, locals_stack, "dict" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "cls" |), "__dict__" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__dict__" |)
             ],
             make_dict []
           |)
@@ -4346,7 +4426,7 @@ Definition slotted_freezable : Value.t -> Value.t -> M :=
 
 Definition S : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "S"
     ],
@@ -4355,8 +4435,9 @@ Definition S : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modify : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `obj` (which must be [`@slotted_freezable`]), and modify
     it by applying `f`. The returned copy will be frozen.
@@ -4364,42 +4445,42 @@ Definition modify : Value.t -> Value.t -> M :=
     [`@slotted_freezable`]: ref:ethereum.base_types.slotted_freezable
     " in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "is_dataclass" |),
+    M.get_name (| globals, locals_stack, "is_dataclass" |),
     make_list [
-      M.get_name (| globals, "obj" |)
+      M.get_name (| globals, locals_stack, "obj" |)
     ],
     make_dict []
   |) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "obj" |);
-      M.get_name (| globals, "SlottedFreezable" |)
+      M.get_name (| globals, locals_stack, "obj" |);
+      M.get_name (| globals, locals_stack, "SlottedFreezable" |)
     ],
     make_dict []
   |) |) in
     let _ := M.assign_local (|
       "new_obj" ,
       M.call (|
-        M.get_name (| globals, "replace" |),
+        M.get_name (| globals, locals_stack, "replace" |),
         make_list [
-          M.get_name (| globals, "obj" |)
+          M.get_name (| globals, locals_stack, "obj" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "f" |),
+    M.get_name (| globals, locals_stack, "f" |),
     make_list [
-      M.get_name (| globals, "new_obj" |)
+      M.get_name (| globals, locals_stack, "new_obj" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "new_obj" |), "_frozen" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "new_obj" |), "_frozen" |),
       Constant.bool true
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "new_obj" |)
+      M.get_name (| globals, locals_stack, "new_obj" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/__init__.v b/CoqOfPython/ethereum/berlin/__init__.v
index 9616412..81fb7fc 100644
--- a/CoqOfPython/ethereum/berlin/__init__.v
+++ b/CoqOfPython/ethereum/berlin/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.__init__".
+Definition globals : Globals.t := "ethereum.berlin.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 12244000
     ],
diff --git a/CoqOfPython/ethereum/berlin/blocks.v b/CoqOfPython/ethereum/berlin/blocks.v
index 8ab9689..092d01e 100644
--- a/CoqOfPython/ethereum/berlin/blocks.v
+++ b/CoqOfPython/ethereum/berlin/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.blocks".
+Definition globals : Globals.t := "ethereum.berlin.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/berlin/bloom.v b/CoqOfPython/ethereum/berlin/bloom.v
index a94f117..b2b59a3 100644
--- a/CoqOfPython/ethereum/berlin/bloom.v
+++ b/CoqOfPython/ethereum/berlin/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.bloom".
+Definition globals : Globals.t := "ethereum.berlin.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_berlin_fork_types_imports_Bloom :
   IsImported globals "ethereum.berlin.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/fork.v b/CoqOfPython/ethereum/berlin/fork.v
index 3a85cfb..fc29b97 100644
--- a/CoqOfPython/ethereum/berlin/fork.v
+++ b/CoqOfPython/ethereum/berlin/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.fork".
+Definition globals : Globals.t := "ethereum.berlin.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -148,7 +150,7 @@ Axiom ethereum_berlin_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -172,7 +174,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -190,10 +192,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -215,8 +217,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -236,13 +239,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -265,7 +269,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -276,9 +280,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -300,17 +304,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -323,13 +327,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -340,20 +344,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -378,111 +383,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -491,9 +496,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -502,9 +507,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -518,8 +523,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -540,101 +546,101 @@ Definition validate_header : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -643,28 +649,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -690,26 +697,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -717,8 +724,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -736,9 +744,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -746,25 +754,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -773,41 +781,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -831,35 +840,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -883,7 +893,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -892,10 +902,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -905,9 +915,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -917,7 +927,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "receipt" |)
+          M.get_name (| globals, locals_stack, "receipt" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -934,8 +944,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -978,22 +989,22 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1002,16 +1013,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1019,9 +1030,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1031,11 +1042,11 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1043,18 +1054,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1062,49 +1073,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1113,56 +1124,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1173,8 +1184,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1199,27 +1211,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1228,9 +1240,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1248,46 +1260,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1298,19 +1310,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1319,23 +1331,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1343,16 +1355,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1366,13 +1378,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1387,11 +1399,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1399,88 +1411,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1493,8 +1505,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1523,44 +1536,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1572,19 +1585,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1597,8 +1610,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1626,30 +1640,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1657,91 +1671,91 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -1749,7 +1763,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -1758,10 +1772,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1769,25 +1783,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -1811,14 +1825,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1826,10 +1840,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1837,20 +1851,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1859,10 +1873,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1870,41 +1884,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1912,31 +1926,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1947,20 +1961,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1973,14 +1987,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1992,27 +2006,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2028,13 +2042,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -2063,17 +2078,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -2088,8 +2103,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2118,14 +2134,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2133,7 +2149,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2141,7 +2157,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2155,9 +2171,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2168,7 +2184,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2187,10 +2203,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -2198,26 +2214,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2233,17 +2249,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2252,8 +2268,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2276,47 +2293,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2324,10 +2341,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2335,19 +2352,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2357,18 +2374,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2380,58 +2397,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2448,10 +2465,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2460,15 +2477,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2485,13 +2502,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2506,8 +2523,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2523,12 +2541,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2539,8 +2557,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2558,19 +2577,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2586,8 +2605,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2603,14 +2623,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2622,8 +2642,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2657,12 +2678,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2673,8 +2694,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2705,18 +2727,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2733,10 +2755,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2753,8 +2775,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2772,8 +2794,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2817,21 +2840,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -2841,11 +2864,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2863,13 +2886,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2878,13 +2901,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -2895,7 +2918,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2905,7 +2928,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2915,13 +2938,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/berlin/fork_types.v b/CoqOfPython/ethereum/berlin/fork_types.v
index 3502e2f..d33ec17 100644
--- a/CoqOfPython/ethereum/berlin/fork_types.v
+++ b/CoqOfPython/ethereum/berlin/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.fork_types".
+Definition globals : Globals.t := "ethereum.berlin.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/berlin/state.v b/CoqOfPython/ethereum/berlin/state.v
index 58d88b0..f9ee9d5 100644
--- a/CoqOfPython/ethereum/berlin/state.v
+++ b/CoqOfPython/ethereum/berlin/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.state".
+Definition globals : Globals.t := "ethereum.berlin.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/transactions.v b/CoqOfPython/ethereum/berlin/transactions.v
index bafffab..8651cfc 100644
--- a/CoqOfPython/ethereum/berlin/transactions.v
+++ b/CoqOfPython/ethereum/berlin/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.transactions".
+Definition globals : Globals.t := "ethereum.berlin.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -90,14 +92,15 @@ Definition AccessListTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -105,17 +108,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -124,10 +127,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -137,9 +140,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -149,7 +152,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "Exception" |),
+              M.get_name (| globals, locals_stack, "Exception" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: JoinedStr *)"
               ],
@@ -162,8 +165,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -171,36 +175,36 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.get_subscript (|
-          M.get_name (| globals, "tx" |),
+          M.get_name (| globals, locals_stack, "tx" |),
           Constant.int 0
         |),
         Constant.int 1
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
             make_list [
-              M.get_name (| globals, "AccessListTransaction" |);
+              M.get_name (| globals, locals_stack, "AccessListTransaction" |);
               M.slice (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 1,
                 Constant.None_,
                 Constant.None_
@@ -213,7 +217,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/berlin/trie.v b/CoqOfPython/ethereum/berlin/trie.v
index 9dbed51..3390556 100644
--- a/CoqOfPython/ethereum/berlin/trie.v
+++ b/CoqOfPython/ethereum/berlin/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.trie".
+Definition globals : Globals.t := "ethereum.berlin.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_berlin_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,34 +124,34 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -187,14 +189,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -218,7 +221,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -234,10 +237,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -246,13 +249,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -261,10 +264,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -273,13 +276,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -288,10 +291,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -300,9 +303,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -310,7 +313,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -327,9 +330,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -339,9 +342,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -350,16 +353,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -369,8 +372,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -380,25 +384,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -410,10 +414,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -421,13 +425,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -442,27 +446,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -486,8 +490,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -504,14 +509,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -522,8 +527,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -543,8 +549,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -552,14 +558,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -571,18 +577,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -602,10 +609,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -613,21 +620,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -640,11 +648,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -652,12 +660,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -665,7 +673,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -680,9 +688,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -690,8 +698,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -728,7 +737,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -739,9 +748,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -752,13 +761,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -766,15 +775,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -784,20 +793,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -815,7 +824,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -823,13 +832,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -838,15 +847,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -856,20 +865,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -887,9 +896,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -897,8 +906,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -915,14 +925,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -933,26 +943,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -960,17 +970,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -982,9 +992,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -992,8 +1002,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1014,9 +1025,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1025,25 +1036,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1051,13 +1062,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1071,9 +1082,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1081,13 +1092,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1095,15 +1106,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1113,22 +1124,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1137,13 +1148,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1164,10 +1176,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1175,14 +1187,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1200,12 +1212,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1218,12 +1230,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1235,18 +1247,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1256,8 +1268,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1281,9 +1294,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1302,12 +1315,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1320,9 +1333,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1333,24 +1346,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1360,8 +1373,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1369,31 +1382,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1408,7 +1421,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1429,7 +1442,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1437,30 +1450,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1480,9 +1493,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1490,7 +1503,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1508,21 +1521,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1530,19 +1543,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1551,8 +1564,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1561,17 +1574,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1584,10 +1597,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/utils/__init__.v b/CoqOfPython/ethereum/berlin/utils/__init__.v
index 0c0263a..f50a7d9 100644
--- a/CoqOfPython/ethereum/berlin/utils/__init__.v
+++ b/CoqOfPython/ethereum/berlin/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.utils.__init__".
+Definition globals : Globals.t := "ethereum.berlin.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/berlin/utils/address.v b/CoqOfPython/ethereum/berlin/utils/address.v
index dd8319d..be75ce6 100644
--- a/CoqOfPython/ethereum/berlin/utils/address.v
+++ b/CoqOfPython/ethereum/berlin/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.utils.address".
+Definition globals : Globals.t := "ethereum.berlin.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_berlin_fork_types_imports_Address :
   IsImported globals "ethereum.berlin.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/utils/hexadecimal.v b/CoqOfPython/ethereum/berlin/utils/hexadecimal.v
index 4b247b7..11e9b6e 100644
--- a/CoqOfPython/ethereum/berlin/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/berlin/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.berlin.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_berlin_fork_types_imports_Root :
   IsImported globals "ethereum.berlin.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/berlin/utils/message.v b/CoqOfPython/ethereum/berlin/utils/message.v
index 6ce9be0..1b6ccca 100644
--- a/CoqOfPython/ethereum/berlin/utils/message.v
+++ b/CoqOfPython/ethereum/berlin/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.utils.message".
+Definition globals : Globals.t := "ethereum.berlin.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_berlin_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.berlin.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/vm/__init__.v b/CoqOfPython/ethereum/berlin/vm/__init__.v
index fcd61d5..eb756e2 100644
--- a/CoqOfPython/ethereum/berlin/vm/__init__.v
+++ b/CoqOfPython/ethereum/berlin/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.__init__".
+Definition globals : Globals.t := "ethereum.berlin.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/exceptions.v b/CoqOfPython/ethereum/berlin/vm/exceptions.v
index 20acb2f..55de82f 100644
--- a/CoqOfPython/ethereum/berlin/vm/exceptions.v
+++ b/CoqOfPython/ethereum/berlin/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.exceptions".
+Definition globals : Globals.t := "ethereum.berlin.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/berlin/vm/gas.v b/CoqOfPython/ethereum/berlin/vm/gas.v
index febe9f3..9a59f10 100644
--- a/CoqOfPython/ethereum/berlin/vm/gas.v
+++ b/CoqOfPython/ethereum/berlin/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.gas".
+Definition globals : Globals.t := "ethereum.berlin.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_berlin_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -326,7 +328,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -336,7 +338,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -356,7 +358,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -376,7 +378,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -406,7 +408,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -416,7 +418,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -426,7 +428,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -446,7 +448,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -475,8 +477,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -489,13 +492,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -506,22 +509,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -531,8 +534,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -552,9 +556,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -564,15 +568,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -581,16 +585,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,7 +624,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -629,12 +634,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -644,14 +649,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -665,9 +670,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -675,20 +680,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -701,8 +706,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -716,16 +721,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -733,9 +738,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -744,13 +749,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -760,10 +765,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -771,8 +776,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -803,13 +809,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -817,32 +823,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -856,18 +862,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -878,15 +884,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -895,8 +901,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -912,9 +919,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/__init__.v b/CoqOfPython/ethereum/berlin/vm/instructions/__init__.v
index 0eae3b0..4ab52a9 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/berlin/vm/instructions/arithmetic.v
index ea8f027..44f4156 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/bitwise.v b/CoqOfPython/ethereum/berlin/vm/instructions/bitwise.v
index f18e7c2..7ca6973 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/block.v b/CoqOfPython/ethereum/berlin/vm/instructions/block.v
index 055cd5d..52e5f80 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/comparison.v b/CoqOfPython/ethereum/berlin/vm/instructions/comparison.v
index 6815b65..3d23118 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/control_flow.v b/CoqOfPython/ethereum/berlin/vm/instructions/control_flow.v
index d084bbb..2a53276 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/environment.v b/CoqOfPython/ethereum/berlin/vm/instructions/environment.v
index 973b275..83b757d 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,35 +1472,35 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/keccak.v b/CoqOfPython/ethereum/berlin/vm/instructions/keccak.v
index 3adfdb0..8f94775 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/log.v b/CoqOfPython/ethereum/berlin/vm/instructions/log.v
index 3add2f4..9b206aa 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_berlin_vm_stack_imports_pop :
   IsImported globals "ethereum.berlin.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/memory.v b/CoqOfPython/ethereum/berlin/vm/instructions/memory.v
index c93d543..b0b7a2b 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/stack.v b/CoqOfPython/ethereum/berlin/vm/instructions/stack.v
index 77860ad..5016b0e 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_berlin_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.berlin.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/storage.v b/CoqOfPython/ethereum/berlin/vm/instructions/storage.v
index 8bf28fd..85002dc 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/instructions/system.v b/CoqOfPython/ethereum/berlin/vm/instructions/system.v
index 313e0af..f1bc612 100644
--- a/CoqOfPython/ethereum/berlin/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/berlin/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.berlin.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -107,28 +109,29 @@ Axiom ethereum_berlin_vm_stack_imports_push :
   IsImported globals "ethereum.berlin.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -138,32 +141,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -173,15 +176,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -197,10 +200,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -210,15 +213,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -239,29 +242,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -281,27 +284,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -309,10 +312,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -320,27 +323,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -353,25 +356,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -383,8 +386,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -396,9 +400,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -406,9 +410,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -416,9 +420,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -426,46 +430,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -474,26 +478,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -508,9 +513,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -518,9 +523,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -528,9 +533,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -539,9 +544,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -552,11 +557,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -566,12 +571,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -582,43 +587,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -627,26 +632,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -658,9 +664,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -668,9 +674,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,63 +684,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -742,24 +749,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -779,11 +786,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -791,10 +798,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -802,7 +809,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -810,10 +817,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -821,27 +828,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -854,23 +861,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -884,16 +891,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -905,14 +912,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -921,8 +928,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -934,12 +942,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -950,12 +958,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -966,9 +974,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -976,9 +984,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -986,9 +994,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -996,9 +1004,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1006,9 +1014,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1016,12 +1024,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1031,28 +1039,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1062,16 +1070,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1079,7 +1087,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1087,7 +1095,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1095,13 +1103,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1109,56 +1117,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1167,25 +1175,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1194,17 +1202,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1214,32 +1222,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1247,14 +1255,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1266,12 +1275,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1282,12 +1291,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1298,9 +1307,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1308,9 +1317,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1318,9 +1327,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1328,9 +1337,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1338,26 +1347,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1367,28 +1376,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1397,13 +1406,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1411,58 +1420,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1471,17 +1480,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1491,32 +1500,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1524,14 +1533,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1543,12 +1553,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1558,28 +1568,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1591,20 +1601,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1617,7 +1627,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1626,33 +1636,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1664,15 +1674,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1680,28 +1690,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1709,33 +1719,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1745,9 +1755,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1755,19 +1765,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1777,15 +1787,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1797,12 +1808,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1813,12 +1824,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1829,9 +1840,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1839,9 +1850,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1849,9 +1860,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1859,9 +1870,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1869,12 +1880,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1884,104 +1895,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1993,12 +2005,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2009,12 +2021,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2025,9 +2037,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2035,9 +2047,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2045,9 +2057,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2055,9 +2067,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2065,12 +2077,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2080,110 +2092,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2195,9 +2208,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2205,9 +2218,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2215,54 +2228,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/interpreter.v b/CoqOfPython/ethereum/berlin/vm/interpreter.v
index c0c52ad..50d490b 100644
--- a/CoqOfPython/ethereum/berlin/vm/interpreter.v
+++ b/CoqOfPython/ethereum/berlin/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.interpreter".
+Definition globals : Globals.t := "ethereum.berlin.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -124,7 +126,7 @@ Axiom ethereum_berlin_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -147,8 +149,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -170,9 +173,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -184,10 +187,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -195,44 +198,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -246,10 +249,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -262,10 +265,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -274,13 +277,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -290,12 +293,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -312,14 +315,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -327,7 +330,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -335,7 +338,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -347,22 +350,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -372,29 +375,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -402,8 +405,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -420,43 +424,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -464,24 +468,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -489,22 +493,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -524,13 +529,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -542,17 +547,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -560,10 +565,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -571,12 +576,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -588,10 +593,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -599,13 +604,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -613,22 +618,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -646,14 +652,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -661,13 +667,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/memory.v b/CoqOfPython/ethereum/berlin/vm/memory.v
index 62e26d1..d953a23 100644
--- a/CoqOfPython/ethereum/berlin/vm/memory.v
+++ b/CoqOfPython/ethereum/berlin/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.memory".
+Definition globals : Globals.t := "ethereum.berlin.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/__init__.v
index 311a52a..d340e5d 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/alt_bn128.v
index 8bfbd17..50f80e6 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_berlin_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.berlin.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/blake2f.v
index 5afc3b4..3cdd347 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_berlin_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.berlin.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ecrecover.v
index 9c5863b..1769bb3 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_berlin_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.berlin.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/identity.v
index 3663ec2..86058e6 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_berlin_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.berlin.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/mapping.v
index 14f0d14..30e740d 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/modexp.v
index aa24c23..70888f6 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ripemd160.v
index a699925..01feab1 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_berlin_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.berlin.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/sha256.v
index b3c060c..d672ada 100644
--- a/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/berlin/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.berlin.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_berlin_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.berlin.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/berlin/vm/runtime.v b/CoqOfPython/ethereum/berlin/vm/runtime.v
index 03bc450..48203e5 100644
--- a/CoqOfPython/ethereum/berlin/vm/runtime.v
+++ b/CoqOfPython/ethereum/berlin/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.runtime".
+Definition globals : Globals.t := "ethereum.berlin.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_berlin_vm_instructions_imports_Ops :
   IsImported globals "ethereum.berlin.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/berlin/vm/stack.v b/CoqOfPython/ethereum/berlin/vm/stack.v
index 812da9c..1788fe7 100644
--- a/CoqOfPython/ethereum/berlin/vm/stack.v
+++ b/CoqOfPython/ethereum/berlin/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.berlin.vm.stack".
+Definition globals : Globals.t := "ethereum.berlin.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_berlin_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.berlin.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/__init__.v b/CoqOfPython/ethereum/byzantium/__init__.v
index 2dfebd4..326e0ea 100644
--- a/CoqOfPython/ethereum/byzantium/__init__.v
+++ b/CoqOfPython/ethereum/byzantium/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.__init__".
+Definition globals : Globals.t := "ethereum.byzantium.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 4370000
     ],
diff --git a/CoqOfPython/ethereum/byzantium/blocks.v b/CoqOfPython/ethereum/byzantium/blocks.v
index 93405c6..e211724 100644
--- a/CoqOfPython/ethereum/byzantium/blocks.v
+++ b/CoqOfPython/ethereum/byzantium/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.blocks".
+Definition globals : Globals.t := "ethereum.byzantium.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/byzantium/bloom.v b/CoqOfPython/ethereum/byzantium/bloom.v
index 4b8bc45..b643468 100644
--- a/CoqOfPython/ethereum/byzantium/bloom.v
+++ b/CoqOfPython/ethereum/byzantium/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.bloom".
+Definition globals : Globals.t := "ethereum.byzantium.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_byzantium_fork_types_imports_Bloom :
   IsImported globals "ethereum.byzantium.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/fork.v b/CoqOfPython/ethereum/byzantium/fork.v
index 87d1e53..cf7386a 100644
--- a/CoqOfPython/ethereum/byzantium/fork.v
+++ b/CoqOfPython/ethereum/byzantium/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.fork".
+Definition globals : Globals.t := "ethereum.byzantium.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_byzantium_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 3,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -176,10 +178,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -201,8 +203,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -222,13 +225,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -251,7 +255,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -262,9 +266,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -286,17 +290,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -309,13 +313,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -326,20 +330,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -364,111 +369,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -477,9 +482,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -488,9 +493,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -504,8 +509,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -526,101 +532,101 @@ Definition validate_header : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -629,28 +635,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -676,26 +683,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -703,8 +710,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -722,9 +730,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -732,25 +740,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -759,41 +767,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -817,35 +826,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -869,13 +879,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -890,8 +900,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -934,51 +945,51 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -986,18 +997,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1005,49 +1016,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1056,56 +1067,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1116,8 +1127,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1142,27 +1154,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1171,9 +1183,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1191,46 +1203,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1241,19 +1253,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1262,23 +1274,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1286,16 +1298,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1309,13 +1321,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1330,11 +1342,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1342,88 +1354,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1436,8 +1448,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1466,44 +1479,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1515,19 +1528,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1540,8 +1553,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1569,30 +1583,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1600,98 +1614,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1699,10 +1713,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1710,20 +1724,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1732,10 +1746,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1743,41 +1757,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1785,31 +1799,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1820,20 +1834,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1846,14 +1860,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1865,27 +1879,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1901,13 +1915,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1936,17 +1951,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1961,8 +1976,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1991,14 +2007,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2006,7 +2022,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2014,7 +2030,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2028,9 +2044,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2041,7 +2057,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2054,14 +2070,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2070,8 +2086,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2094,47 +2111,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2143,12 +2160,12 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -2158,18 +2175,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_pre155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |)
+                  M.get_name (| globals, locals_stack, "tx" |)
                 ],
                 make_dict []
               |)
@@ -2181,58 +2198,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 35
                 |),
                 BinOp.mult (|
-                  M.get_name (| globals, "chain_id" |),
+                  M.get_name (| globals, locals_stack, "chain_id" |),
                   Constant.int 2
                 |)
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |);
-                  M.get_name (| globals, "chain_id" |)
+                  M.get_name (| globals, locals_stack, "tx" |);
+                  M.get_name (| globals, locals_stack, "chain_id" |)
                 ],
                 make_dict []
               |)
@@ -2244,13 +2261,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2265,8 +2282,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2282,12 +2300,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2298,8 +2316,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2317,19 +2336,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2345,8 +2364,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2380,12 +2400,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2396,8 +2416,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2428,18 +2449,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2456,10 +2477,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2476,8 +2497,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2495,8 +2516,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2540,21 +2562,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -2564,11 +2586,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2586,13 +2608,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2601,13 +2623,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -2618,7 +2640,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2628,7 +2650,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2638,13 +2660,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/byzantium/fork_types.v b/CoqOfPython/ethereum/byzantium/fork_types.v
index b564ee7..bf20981 100644
--- a/CoqOfPython/ethereum/byzantium/fork_types.v
+++ b/CoqOfPython/ethereum/byzantium/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.fork_types".
+Definition globals : Globals.t := "ethereum.byzantium.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/byzantium/state.v b/CoqOfPython/ethereum/byzantium/state.v
index 525fbd8..a202e2d 100644
--- a/CoqOfPython/ethereum/byzantium/state.v
+++ b/CoqOfPython/ethereum/byzantium/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.state".
+Definition globals : Globals.t := "ethereum.byzantium.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,8 +710,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -714,10 +732,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -725,9 +743,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -737,12 +755,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -753,8 +771,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -775,10 +794,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -786,15 +805,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -804,12 +823,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -822,8 +841,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -842,10 +862,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -854,7 +874,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -868,9 +888,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -880,12 +900,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -898,28 +918,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -929,36 +950,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -975,19 +998,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1003,21 +1027,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1029,8 +1053,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1044,19 +1069,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1073,19 +1099,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1100,11 +1127,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/byzantium/transactions.v b/CoqOfPython/ethereum/byzantium/transactions.v
index d474dfc..9fcc79a 100644
--- a/CoqOfPython/ethereum/byzantium/transactions.v
+++ b/CoqOfPython/ethereum/byzantium/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.transactions".
+Definition globals : Globals.t := "ethereum.byzantium.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/byzantium/trie.v b/CoqOfPython/ethereum/byzantium/trie.v
index 4999d6e..8253548 100644
--- a/CoqOfPython/ethereum/byzantium/trie.v
+++ b/CoqOfPython/ethereum/byzantium/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.trie".
+Definition globals : Globals.t := "ethereum.byzantium.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_byzantium_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/utils/__init__.v b/CoqOfPython/ethereum/byzantium/utils/__init__.v
index 418c984..8226fd5 100644
--- a/CoqOfPython/ethereum/byzantium/utils/__init__.v
+++ b/CoqOfPython/ethereum/byzantium/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.utils.__init__".
+Definition globals : Globals.t := "ethereum.byzantium.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/byzantium/utils/address.v b/CoqOfPython/ethereum/byzantium/utils/address.v
index f8a4ecd..0ba31e5 100644
--- a/CoqOfPython/ethereum/byzantium/utils/address.v
+++ b/CoqOfPython/ethereum/byzantium/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.utils.address".
+Definition globals : Globals.t := "ethereum.byzantium.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_byzantium_fork_types_imports_Address :
   IsImported globals "ethereum.byzantium.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -56,11 +59,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -75,8 +78,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -96,14 +100,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -115,7 +119,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -124,9 +128,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -134,9 +138,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/utils/hexadecimal.v b/CoqOfPython/ethereum/byzantium/utils/hexadecimal.v
index 5540c16..6424c2a 100644
--- a/CoqOfPython/ethereum/byzantium/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/byzantium/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.byzantium.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_byzantium_fork_types_imports_Root :
   IsImported globals "ethereum.byzantium.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/byzantium/utils/message.v b/CoqOfPython/ethereum/byzantium/utils/message.v
index c60fbeb..195323c 100644
--- a/CoqOfPython/ethereum/byzantium/utils/message.v
+++ b/CoqOfPython/ethereum/byzantium/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.utils.message".
+Definition globals : Globals.t := "ethereum.byzantium.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_byzantium_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.byzantium.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -85,10 +88,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -97,20 +100,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -124,7 +127,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -133,7 +136,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -142,10 +145,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -153,19 +156,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -174,14 +177,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -192,7 +195,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -204,7 +207,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/vm/__init__.v b/CoqOfPython/ethereum/byzantium/vm/__init__.v
index b02d05c..34ff2a1 100644
--- a/CoqOfPython/ethereum/byzantium/vm/__init__.v
+++ b/CoqOfPython/ethereum/byzantium/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.__init__".
+Definition globals : Globals.t := "ethereum.byzantium.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -93,8 +95,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -107,30 +110,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -138,19 +141,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -162,8 +165,9 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -178,15 +182,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -199,8 +203,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -208,19 +212,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -236,7 +240,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/exceptions.v b/CoqOfPython/ethereum/byzantium/vm/exceptions.v
index 7375e6c..0e595d2 100644
--- a/CoqOfPython/ethereum/byzantium/vm/exceptions.v
+++ b/CoqOfPython/ethereum/byzantium/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.exceptions".
+Definition globals : Globals.t := "ethereum.byzantium.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/byzantium/vm/gas.v b/CoqOfPython/ethereum/byzantium/vm/gas.v
index bd2fb66..bf9d020 100644
--- a/CoqOfPython/ethereum/byzantium/vm/gas.v
+++ b/CoqOfPython/ethereum/byzantium/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.gas".
+Definition globals : Globals.t := "ethereum.byzantium.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_byzantium_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 400
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -436,7 +438,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -465,8 +467,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -479,13 +482,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -496,22 +499,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -521,8 +524,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -542,9 +546,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -554,15 +558,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -571,16 +575,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,12 +624,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -634,14 +639,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -655,9 +660,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -665,20 +670,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -691,8 +696,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -706,16 +711,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -723,9 +728,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -734,13 +739,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -750,10 +755,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -761,8 +766,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -793,13 +799,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -807,32 +813,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -846,18 +852,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -868,15 +874,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -885,8 +891,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -902,9 +909,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/__init__.v b/CoqOfPython/ethereum/byzantium/vm/instructions/__init__.v
index f76e351..4299835 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/byzantium/vm/instructions/arithmetic.v
index 554d565..3a47aa4 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/bitwise.v b/CoqOfPython/ethereum/byzantium/vm/instructions/bitwise.v
index 78deb13..1ceeb8c 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/block.v b/CoqOfPython/ethereum/byzantium/vm/instructions/block.v
index deb5d8d..e750866 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/comparison.v b/CoqOfPython/ethereum/byzantium/vm/instructions/comparison.v
index b282bad..0a28fba 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/control_flow.v b/CoqOfPython/ethereum/byzantium/vm/instructions/control_flow.v
index 01a71f7..1cca22a 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/environment.v b/CoqOfPython/ethereum/byzantium/vm/instructions/environment.v
index 150687d..03bc9e7 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -68,8 +70,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -81,21 +84,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -104,14 +107,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -124,12 +128,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -138,42 +142,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -186,21 +191,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -209,14 +214,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -228,21 +234,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -251,14 +257,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -270,31 +277,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -308,30 +316,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -342,13 +350,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -357,14 +365,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -376,24 +385,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -405,14 +414,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -428,9 +438,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -438,9 +448,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -448,9 +458,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -459,12 +469,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -477,76 +487,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -558,24 +569,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -587,14 +598,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -610,9 +622,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -620,9 +632,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -630,9 +642,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -641,12 +653,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -659,76 +671,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -740,21 +753,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -763,14 +776,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -783,12 +797,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -797,26 +811,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -828,23 +842,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -857,12 +872,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,9 +888,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -883,9 +898,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -893,9 +908,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -904,12 +919,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -922,52 +937,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -975,34 +990,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1013,24 +1029,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1042,14 +1058,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1061,9 +1078,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,9 +1088,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1081,9 +1098,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1092,12 +1109,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1110,101 +1127,101 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/keccak.v b/CoqOfPython/ethereum/byzantium/vm/instructions/keccak.v
index c54b6cc..c95d552 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/log.v b/CoqOfPython/ethereum/byzantium/vm/instructions/log.v
index 4f0424b..31233e1 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_byzantium_vm_stack_imports_pop :
   IsImported globals "ethereum.byzantium.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/memory.v b/CoqOfPython/ethereum/byzantium/vm/instructions/memory.v
index ff2aeb3..92f11c5 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/stack.v b/CoqOfPython/ethereum/byzantium/vm/instructions/stack.v
index 2b2ad26..9d68ac8 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_byzantium_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.byzantium.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/storage.v b/CoqOfPython/ethereum/byzantium/vm/instructions/storage.v
index 64a99f4..a14dbd9 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -48,8 +50,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -64,9 +67,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -75,43 +78,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -125,9 +129,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -138,9 +142,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -148,11 +152,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -162,12 +166,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -176,14 +180,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -192,12 +196,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -206,8 +210,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -215,34 +219,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/instructions/system.v b/CoqOfPython/ethereum/byzantium/vm/instructions/system.v
index e75fc6e..4cbca10 100644
--- a/CoqOfPython/ethereum/byzantium/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/byzantium/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.byzantium.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -98,8 +100,9 @@ Axiom ethereum_byzantium_vm_stack_imports_push :
   IsImported globals "ethereum.byzantium.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -112,9 +115,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -122,9 +125,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -132,9 +135,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,23 +145,23 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -166,12 +169,12 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -181,40 +184,40 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -222,14 +225,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -242,15 +245,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -266,10 +269,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -278,11 +281,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -293,8 +296,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -303,29 +306,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -340,27 +343,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -368,10 +371,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -379,27 +382,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.assign (|
-                  M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -412,25 +415,25 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.assign (|
-                  M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
                   Constant.bytes ""
                 |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -445,14 +448,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -464,9 +468,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -474,9 +478,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -484,63 +488,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -548,24 +553,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -585,11 +590,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -597,10 +602,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -608,7 +613,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -616,10 +621,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -627,27 +632,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -660,23 +665,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -690,16 +695,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -711,14 +716,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -727,8 +732,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -740,12 +746,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -756,12 +762,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -772,9 +778,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -782,9 +788,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -792,9 +798,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -802,9 +808,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -812,9 +818,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -822,12 +828,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -839,15 +845,15 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             M.call (|
-              M.get_name (| globals, "is_account_alive" |),
+              M.get_name (| globals, locals_stack, "is_account_alive" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "to" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "to" |)
               ],
               make_dict []
             |)
@@ -856,7 +862,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -864,7 +870,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -872,13 +878,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -886,56 +892,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -944,25 +950,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -971,17 +977,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -991,32 +997,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1024,14 +1030,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1043,12 +1050,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1059,12 +1066,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1075,9 +1082,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1085,9 +1092,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1095,9 +1102,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1105,9 +1112,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1115,26 +1122,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1145,13 +1152,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1159,58 +1166,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1219,17 +1226,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1239,32 +1246,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1272,14 +1279,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1291,12 +1299,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1306,27 +1314,27 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1339,7 +1347,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1348,33 +1356,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1386,15 +1394,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1402,28 +1410,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1431,33 +1439,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1467,9 +1475,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1477,19 +1485,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1499,15 +1507,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1519,12 +1528,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1535,12 +1544,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1551,9 +1560,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1561,9 +1570,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1571,9 +1580,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1581,9 +1590,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1591,12 +1600,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1605,76 +1614,77 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1686,12 +1696,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1702,12 +1712,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1718,9 +1728,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1728,9 +1738,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1738,9 +1748,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1748,9 +1758,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1758,12 +1768,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1772,82 +1782,83 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -1859,9 +1870,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1869,9 +1880,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1879,54 +1890,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/interpreter.v b/CoqOfPython/ethereum/byzantium/vm/interpreter.v
index 53559db..1c71f79 100644
--- a/CoqOfPython/ethereum/byzantium/vm/interpreter.v
+++ b/CoqOfPython/ethereum/byzantium/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.interpreter".
+Definition globals : Globals.t := "ethereum.byzantium.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -122,7 +124,7 @@ Axiom ethereum_byzantium_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -145,8 +147,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -168,9 +171,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -182,10 +185,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -193,44 +196,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -244,10 +247,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -260,10 +263,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -272,13 +275,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -288,12 +291,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -310,14 +313,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -325,7 +328,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -333,7 +336,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -345,48 +348,48 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -394,8 +397,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -412,35 +416,35 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -448,24 +452,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -473,22 +477,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -508,13 +513,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -526,17 +531,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -544,10 +549,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -555,12 +560,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -572,10 +577,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -583,13 +588,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -597,22 +602,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -630,14 +636,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -645,13 +651,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/memory.v b/CoqOfPython/ethereum/byzantium/vm/memory.v
index 148e6c5..20c1f88 100644
--- a/CoqOfPython/ethereum/byzantium/vm/memory.v
+++ b/CoqOfPython/ethereum/byzantium/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.memory".
+Definition globals : Globals.t := "ethereum.byzantium.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/__init__.v
index d82e958..7aff869 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/alt_bn128.v
index 01b9f2c..f90e2a8 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_byzantium_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.byzantium.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 500
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 40000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 80000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ecrecover.v
index 6daeeb3..1da26e6 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_byzantium_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.byzantium.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/identity.v
index 7f914dd..be43993 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_byzantium_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.byzantium.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/mapping.v
index 7088817..a9bc261 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/modexp.v
index d8d7f8d..aa931ce 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,7 +37,7 @@ Axiom ethereum_byzantium_vm_memory_imports_buffer_read :
 
 Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -44,34 +46,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -87,21 +90,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -117,21 +120,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -148,36 +151,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -192,7 +195,7 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "exp_length" |),
+          M.get_name (| globals, locals_stack, "exp_length" |),
           Constant.int 32
         |),
       (* then *)
@@ -200,15 +203,15 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   Constant.int 0;
                   BinOp.sub (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                       make_list [],
                       make_dict []
                     |),
@@ -227,16 +230,16 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               BinOp.add (|
                 BinOp.mult (|
                   Constant.int 8,
                   BinOp.sub (|
                     M.call (|
-                      M.get_name (| globals, "int" |),
+                      M.get_name (| globals, locals_stack, "int" |),
                       make_list [
-                        M.get_name (| globals, "exp_length" |)
+                        M.get_name (| globals, locals_stack, "exp_length" |)
                       ],
                       make_dict []
                     |),
@@ -244,12 +247,12 @@ Definition modexp : Value.t -> Value.t -> M :=
                   |)
                 |),
                 M.call (|
-                  M.get_name (| globals, "max" |),
+                  M.get_name (| globals, locals_stack, "max" |),
                   make_list [
                     Constant.int 0;
                     BinOp.sub (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                         make_list [],
                         make_dict []
                       |),
@@ -266,22 +269,22 @@ Definition modexp : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.floor_div (|
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "get_mult_complexity" |),
+            M.get_name (| globals, locals_stack, "get_mult_complexity" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "max" |),
+                    M.get_name (| globals, locals_stack, "max" |),
                     make_list [
-                      M.get_name (| globals, "base_length" |);
-                      M.get_name (| globals, "modulus_length" |)
+                      M.get_name (| globals, locals_stack, "base_length" |);
+                      M.get_name (| globals, locals_stack, "modulus_length" |)
                     ],
                     make_dict []
                   |)
@@ -292,11 +295,11 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "adjusted_exp_length" |);
+              M.get_name (| globals, locals_stack, "adjusted_exp_length" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 1
                 ],
@@ -306,7 +309,7 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |)
         |),
-        M.get_name (| globals, "GQUADDIVISOR" |)
+        M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
       |)
     ],
     make_dict []
@@ -316,12 +319,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -329,9 +332,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -347,20 +350,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -371,14 +374,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -389,21 +392,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -415,39 +418,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -455,7 +458,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -466,8 +469,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_mult_complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing Karatsuba multiplication.
     " in
@@ -475,14 +479,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 64
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.pow (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 2
           |)
         |) in
@@ -493,7 +497,7 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "x" |),
+              M.get_name (| globals, locals_stack, "x" |),
               Constant.int 1024
             |),
           (* then *)
@@ -503,14 +507,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 4
                   |),
                   BinOp.mult (|
                     Constant.int 96,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 3072
@@ -524,14 +528,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 16
                   |),
                   BinOp.mult (|
                     Constant.int 480,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 199680
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ripemd160.v
index dcf5699..d405920 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_byzantium_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.byzantium.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/sha256.v
index 3059153..7669a50 100644
--- a/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/byzantium/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.byzantium.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_byzantium_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.byzantium.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/byzantium/vm/runtime.v b/CoqOfPython/ethereum/byzantium/vm/runtime.v
index 0417135..e5b4870 100644
--- a/CoqOfPython/ethereum/byzantium/vm/runtime.v
+++ b/CoqOfPython/ethereum/byzantium/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.runtime".
+Definition globals : Globals.t := "ethereum.byzantium.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_byzantium_vm_instructions_imports_Ops :
   IsImported globals "ethereum.byzantium.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/byzantium/vm/stack.v b/CoqOfPython/ethereum/byzantium/vm/stack.v
index e9c738b..b368020 100644
--- a/CoqOfPython/ethereum/byzantium/vm/stack.v
+++ b/CoqOfPython/ethereum/byzantium/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.byzantium.vm.stack".
+Definition globals : Globals.t := "ethereum.byzantium.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_byzantium_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.byzantium.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/__init__.v b/CoqOfPython/ethereum/cancun/__init__.v
index 2ad1a6a..c87f204 100644
--- a/CoqOfPython/ethereum/cancun/__init__.v
+++ b/CoqOfPython/ethereum/cancun/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.__init__".
+Definition globals : Globals.t := "ethereum.cancun.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -15,7 +17,7 @@ Axiom ethereum_fork_criteria_imports_ByTimestamp :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByTimestamp" |),
+    M.get_name (| globals, locals_stack, "ByTimestamp" |),
     make_list [
       Constant.int 1710338135
     ],
diff --git a/CoqOfPython/ethereum/cancun/blocks.v b/CoqOfPython/ethereum/cancun/blocks.v
index 540810b..6d98eb6 100644
--- a/CoqOfPython/ethereum/cancun/blocks.v
+++ b/CoqOfPython/ethereum/cancun/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.blocks".
+Definition globals : Globals.t := "ethereum.cancun.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/cancun/bloom.v b/CoqOfPython/ethereum/cancun/bloom.v
index 8795d1e..0836db3 100644
--- a/CoqOfPython/ethereum/cancun/bloom.v
+++ b/CoqOfPython/ethereum/cancun/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.bloom".
+Definition globals : Globals.t := "ethereum.cancun.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_cancun_fork_types_imports_Bloom :
   IsImported globals "ethereum.cancun.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/fork.v b/CoqOfPython/ethereum/cancun/fork.v
index 678991e..be9035f 100644
--- a/CoqOfPython/ethereum/cancun/fork.v
+++ b/CoqOfPython/ethereum/cancun/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.fork".
+Definition globals : Globals.t := "ethereum.cancun.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -186,10 +188,10 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -202,7 +204,7 @@ Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition SYSTEM_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0xfffffffffffffffffffffffffffffffffffffffe"
     ],
@@ -212,7 +214,7 @@ Definition SYSTEM_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BEACON_ROOTS_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02"
     ],
@@ -222,7 +224,7 @@ Definition BEACON_ROOTS_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SYSTEM_TRANSACTION_GAS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30000000
     ],
@@ -249,8 +251,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -270,13 +273,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -299,7 +303,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -310,9 +314,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -334,17 +338,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -357,13 +361,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -374,20 +378,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -412,159 +417,159 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.assign_local (|
       "excess_blob_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_excess_blob_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_excess_blob_gas" |),
         make_list [
-          M.get_name (| globals, "parent_header" |)
+          M.get_name (| globals, locals_stack, "parent_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "excess_blob_gas" |),
-        M.get_name (| globals, "excess_blob_gas" |)
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "excess_blob_gas" |),
+        M.get_name (| globals, locals_stack, "excess_blob_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "block" |), "ommers" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |),
         make_tuple [  ]
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "prev_randao" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |);
-          M.get_field (| M.get_name (| globals, "block" |), "withdrawals" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_beacon_block_root" |);
-          M.get_name (| globals, "excess_blob_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "prev_randao" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "withdrawals" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_beacon_block_root" |);
+          M.get_name (| globals, locals_stack, "excess_blob_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "withdrawals_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "withdrawals_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "withdrawals_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "withdrawals_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "blob_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "blob_gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "blob_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "blob_gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -573,9 +578,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -584,9 +589,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -600,8 +605,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -624,22 +630,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -647,14 +653,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -663,40 +669,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -706,8 +712,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -716,36 +722,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -754,9 +760,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -764,8 +770,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -784,124 +791,124 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
         Constant.int 0
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |),
         Constant.bytes "0000000000000000"
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -910,21 +917,22 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "tx"; "gas_available"; "chain_id"; "base_fee_per_gas"; "excess_blob_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "tx"; "gas_available"; "chain_id"; "base_fee_per_gas"; "excess_blob_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -962,17 +970,17 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -982,7 +990,7 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
           BinOp.sub (|
             BinOp.pow (|
               Constant.int 2,
@@ -993,7 +1001,7 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -1004,9 +1012,9 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
             M.call (|
-              M.get_name (| globals, "Bytes0" |),
+              M.get_name (| globals, locals_stack, "Bytes0" |),
               make_list [
                 Constant.bytes ""
               ],
@@ -1016,22 +1024,22 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             Compare.gt (|
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "tx" |), "data" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |)
                 ],
                 make_dict []
               |),
               BinOp.mult (|
                 Constant.int 2,
-                M.get_name (| globals, "MAX_CODE_SIZE" |)
+                M.get_name (| globals, locals_stack, "MAX_CODE_SIZE" |)
               |)
             |)
           ))
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -1041,12 +1049,12 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-          M.get_name (| globals, "gas_available" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+          M.get_name (| globals, locals_stack, "gas_available" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -1055,10 +1063,10 @@ Definition check_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1066,10 +1074,10 @@ Definition check_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1078,10 +1086,10 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "FeeMarketTransaction" |); M.get_name (| globals, "BlobTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "FeeMarketTransaction" |); M.get_name (| globals, locals_stack, "BlobTransaction" |) ]
           ],
           make_dict []
         |),
@@ -1091,12 +1099,12 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt (|
-              M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1106,12 +1114,12 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt (|
-              M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-              M.get_name (| globals, "base_fee_per_gas" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+              M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1120,12 +1128,12 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -1134,15 +1142,15 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1152,12 +1160,12 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt (|
-              M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-              M.get_name (| globals, "base_fee_per_gas" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+              M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1165,13 +1173,13 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           )) |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1180,10 +1188,10 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "BlobTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "BlobTransaction" |)
           ],
           make_dict []
         |),
@@ -1193,16 +1201,16 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             UnOp.not (| M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-                M.get_name (| globals, "Address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |) |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1213,9 +1221,9 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "tx" |), "blob_versioned_hashes" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "blob_versioned_hashes" |)
                 ],
                 make_dict []
               |),
@@ -1223,7 +1231,7 @@ Definition check_transaction : Value.t -> Value.t -> M :=
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1231,24 +1239,24 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           )) |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "blob_versioned_hash" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "blob_versioned_hashes" |),
+            M.get_name (| globals, locals_stack, "blob_versioned_hash" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "blob_versioned_hashes" |),
             ltac:(M.monadic (
               let _ :=
                 (* if *)
                 M.if_then_else (|
                   Compare.not_eq (|
                     M.slice (|
-                      M.get_name (| globals, "blob_versioned_hash" |),
+                      M.get_name (| globals, locals_stack, "blob_versioned_hash" |),
                       Constant.int 0,
                       Constant.int 1,
                       Constant.None_
                     |),
-                    M.get_name (| globals, "VERSIONED_HASH_VERSION_KZG" |)
+                    M.get_name (| globals, locals_stack, "VERSIONED_HASH_VERSION_KZG" |)
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1264,18 +1272,18 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt (|
-              M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_blob_gas" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_blob_gas" |),
               M.call (|
-                M.get_name (| globals, "calculate_blob_gas_price" |),
+                M.get_name (| globals, locals_stack, "calculate_blob_gas_price" |),
                 make_list [
-                  M.get_name (| globals, "excess_blob_gas" |)
+                  M.get_name (| globals, locals_stack, "excess_blob_gas" |)
                 ],
                 make_dict []
               |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
@@ -1286,18 +1294,18 @@ Definition check_transaction : Value.t -> Value.t -> M :=
           "max_gas_fee",
           BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "calculate_total_blob_gas" |),
+      M.get_name (| globals, locals_stack, "calculate_total_blob_gas" |),
       make_list [
-        M.get_name (| globals, "tx" |)
+        M.get_name (| globals, locals_stack, "tx" |)
       ],
       make_dict []
     |),
-    M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_blob_gas" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_blob_gas" |)
   |)
         |) in
         let _ := M.assign_local (|
           "blob_versioned_hashes" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "blob_versioned_hashes" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "blob_versioned_hashes" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1309,53 +1317,54 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender" |); M.get_name (| globals, "effective_gas_price" |); M.get_name (| globals, "blob_versioned_hashes" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender" |); M.get_name (| globals, locals_stack, "effective_gas_price" |); M.get_name (| globals, locals_stack, "blob_versioned_hashes" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -1379,7 +1388,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -1388,10 +1397,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1401,9 +1410,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1416,10 +1425,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1429,9 +1438,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1444,10 +1453,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "BlobTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "BlobTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -1457,9 +1466,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "03",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "receipt" |)
+                        M.get_name (| globals, locals_stack, "receipt" |)
                       ],
                       make_dict []
                     |)
@@ -1469,7 +1478,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "receipt" |)
+                  M.get_name (| globals, locals_stack, "receipt" |)
                 |) in
                 M.pure Constant.None_
               )) |) in
@@ -1490,8 +1499,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id"; "withdrawals"; "parent_beacon_block_root"; "excess_blob_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id"; "withdrawals"; "parent_beacon_block_root"; "excess_blob_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1543,7 +1553,7 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "blob_gas_used" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -1552,7 +1562,7 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
@@ -1561,10 +1571,10 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beacon_block_roots_contract_code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "BEACON_ROOTS_ADDRESS" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "BEACON_ROOTS_ADDRESS" |)
         ],
         make_dict []
       |), "code" |)
@@ -1572,7 +1582,7 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "system_tx_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -1580,7 +1590,7 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "system_tx_env" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
         make_list [],
         make_dict []
       |)
@@ -1588,33 +1598,33 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "system_tx_output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "system_tx_message" |);
-          M.get_name (| globals, "system_tx_env" |)
+          M.get_name (| globals, locals_stack, "system_tx_message" |);
+          M.get_name (| globals, locals_stack, "system_tx_env" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_touched_empty_accounts" |),
+    M.get_name (| globals, locals_stack, "destroy_touched_empty_accounts" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "system_tx_env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "system_tx_output" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "system_tx_env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "system_tx_output" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1623,16 +1633,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1640,9 +1650,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1650,16 +1660,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |); M.get_name (| globals, "blob_versioned_hashes" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |); M.get_name (| globals, locals_stack, "blob_versioned_hashes" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "state" |);
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "excess_blob_gas" |)
+                M.get_name (| globals, locals_stack, "state" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "excess_blob_gas" |)
               ],
               make_dict []
             |)
@@ -1667,18 +1677,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1686,57 +1696,57 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "blob_gas_used",
             M.call (|
-    M.get_name (| globals, "calculate_total_blob_gas" |),
+    M.get_name (| globals, locals_stack, "calculate_total_blob_gas" |),
     make_list [
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |)
@@ -1748,55 +1758,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_name (| globals, "blob_gas_used" |),
-        M.get_name (| globals, "MAX_BLOB_GAS_PER_BLOCK" |)
+        M.get_name (| globals, locals_stack, "blob_gas_used" |),
+        M.get_name (| globals, locals_stack, "MAX_BLOB_GAS_PER_BLOCK" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "wd" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "wd" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "withdrawals" |)
+        M.get_name (| globals, locals_stack, "withdrawals" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "withdrawals_trie" |);
+      M.get_name (| globals, locals_stack, "withdrawals_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1804,9 +1814,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "wd" |)
+          M.get_name (| globals, locals_stack, "wd" |)
         ],
         make_dict []
       |)
@@ -1814,10 +1824,10 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "process_withdrawal" |),
+    M.get_name (| globals, locals_stack, "process_withdrawal" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "wd" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "wd" |)
     ],
     make_dict []
   |) in
@@ -1825,20 +1835,20 @@ Definition apply_body : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_name (| globals, "state" |);
-                  M.get_field (| M.get_name (| globals, "wd" |), "address" |)
+                  M.get_name (| globals, locals_stack, "state" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "wd" |), "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |)
     ],
     make_dict []
   |) in
@@ -1855,39 +1865,39 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "withdrawals_trie" |)
+              M.get_name (| globals, locals_stack, "withdrawals_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "blob_gas_used" |)
+          M.get_name (| globals, locals_stack, "blob_gas_used" |)
         ],
         make_dict []
       |)
@@ -1895,8 +1905,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1925,15 +1936,15 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1942,10 +1953,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "BlobTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "BlobTransaction" |)
           ],
           make_dict []
         |),
@@ -1954,10 +1965,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "blob_gas_fee" ,
           M.call (|
-            M.get_name (| globals, "calculate_data_fee" |),
+            M.get_name (| globals, locals_stack, "calculate_data_fee" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "excess_blob_gas" |);
-              M.get_name (| globals, "tx" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "excess_blob_gas" |);
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |)
@@ -1968,7 +1979,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "blob_gas_fee" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -1980,28 +1991,28 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
@@ -2009,25 +2020,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
         BinOp.sub (|
-          M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-          M.get_name (| globals, "effective_gas_fee" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+          M.get_name (| globals, locals_stack, "effective_gas_fee" |)
         |),
-        M.get_name (| globals, "blob_gas_fee" |)
+        M.get_name (| globals, locals_stack, "blob_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2035,15 +2046,15 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -2051,10 +2062,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |); M.get_name (| globals, "BlobTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |); M.get_name (| globals, locals_stack, "BlobTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2062,25 +2073,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -2104,14 +2115,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2119,10 +2130,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2130,20 +2141,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -2152,17 +2163,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2170,41 +2181,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -2212,31 +2223,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -2247,20 +2258,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -2273,14 +2284,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2291,21 +2302,22 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_touched_empty_accounts" |),
+    M.get_name (| globals, locals_stack, "destroy_touched_empty_accounts" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2334,14 +2346,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2349,7 +2361,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2357,7 +2369,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2371,9 +2383,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2385,20 +2397,20 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "create_cost" ,
           BinOp.add (|
-            M.get_name (| globals, "TX_CREATE_COST" |),
+            M.get_name (| globals, locals_stack, "TX_CREATE_COST" |),
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "init_code_cost" |),
+                  M.get_name (| globals, locals_stack, "init_code_cost" |),
                   make_list [
                     M.call (|
-                      M.get_name (| globals, "Uint" |),
+                      M.get_name (| globals, locals_stack, "Uint" |),
                       make_list [
                         M.call (|
-                          M.get_name (| globals, "len" |),
+                          M.get_name (| globals, locals_stack, "len" |),
                           make_list [
-                            M.get_field (| M.get_name (| globals, "tx" |), "data" |)
+                            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |)
                           ],
                           make_dict []
                         |)
@@ -2430,10 +2442,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |); M.get_name (| globals, "BlobTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |); M.get_name (| globals, locals_stack, "BlobTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2441,26 +2453,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2476,17 +2488,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2495,8 +2507,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2519,47 +2532,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2567,10 +2580,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2578,19 +2591,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2600,18 +2613,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2623,58 +2636,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2691,10 +2704,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2703,15 +2716,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2726,10 +2739,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2738,15 +2751,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2761,10 +2774,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "tx" |);
-                        M.get_name (| globals, "BlobTransaction" |)
+                        M.get_name (| globals, locals_stack, "tx" |);
+                        M.get_name (| globals, locals_stack, "BlobTransaction" |)
                       ],
                       make_dict []
                     |),
@@ -2773,15 +2786,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "public_key" ,
                       M.call (|
-                        M.get_name (| globals, "secp256k1_recover" |),
+                        M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                         make_list [
-                          M.get_name (| globals, "r" |);
-                          M.get_name (| globals, "s" |);
-                          M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                          M.get_name (| globals, locals_stack, "r" |);
+                          M.get_name (| globals, locals_stack, "s" |);
+                          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                           M.call (|
-                            M.get_name (| globals, "signing_hash_4844" |),
+                            M.get_name (| globals, locals_stack, "signing_hash_4844" |),
                             make_list [
-                              M.get_name (| globals, "tx" |)
+                              M.get_name (| globals, locals_stack, "tx" |)
                             ],
                             make_dict []
                           |)
@@ -2802,13 +2815,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2823,8 +2836,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2840,12 +2854,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2856,8 +2870,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2875,19 +2890,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2903,8 +2918,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2920,14 +2936,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2939,8 +2955,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -2956,14 +2973,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2975,8 +2992,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_4844 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP-4844 signature.
 
@@ -2992,14 +3010,14 @@ Definition signing_hash_4844 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "03",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_blob_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "blob_versioned_hashes" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_blob_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "blob_versioned_hashes" |) ]
               ],
               make_dict []
             |)
@@ -3011,8 +3029,9 @@ Definition signing_hash_4844 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -3046,12 +3065,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -3062,8 +3081,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -3094,18 +3114,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3122,10 +3142,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3142,8 +3162,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
diff --git a/CoqOfPython/ethereum/cancun/fork_types.v b/CoqOfPython/ethereum/cancun/fork_types.v
index dd0de4b..306871b 100644
--- a/CoqOfPython/ethereum/cancun/fork_types.v
+++ b/CoqOfPython/ethereum/cancun/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.fork_types".
+Definition globals : Globals.t := "ethereum.cancun.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,19 +44,19 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition VersionedHash : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -69,15 +71,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -86,12 +89,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/cancun/state.v b/CoqOfPython/ethereum/cancun/state.v
index 897c75a..26b9a8e 100644
--- a/CoqOfPython/ethereum/cancun/state.v
+++ b/CoqOfPython/ethereum/cancun/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.state".
+Definition globals : Globals.t := "ethereum.cancun.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -100,21 +102,23 @@ Definition TransientStorage : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "transient_storage" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "transient_storage" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -129,12 +133,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The transient storage of the transaction.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -142,7 +146,7 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "transient_storage" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_snapshots" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: DictComp *)"
     ],
@@ -151,8 +155,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "transient_storage" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "transient_storage" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -164,18 +169,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The transient storage of the transaction.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -185,15 +190,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "transient_storage" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "transient_storage" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "transient_storage" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -206,9 +212,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The transient storage of the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -216,11 +222,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -230,9 +236,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "transient_storage" |), "_tries" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_tries" |),
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "transient_storage" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -240,8 +246,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -264,10 +271,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -276,31 +283,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -320,22 +328,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -350,19 +359,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -378,18 +388,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -397,8 +407,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -413,14 +424,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -430,8 +441,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -449,17 +461,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -481,9 +494,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -492,14 +505,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -514,30 +527,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -555,10 +569,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -567,9 +581,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -578,7 +592,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -586,17 +600,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -604,11 +618,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -616,14 +630,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -633,8 +647,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -650,23 +665,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -676,15 +691,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -698,13 +714,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -712,8 +728,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -732,10 +749,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -745,8 +762,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -766,10 +784,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -777,9 +795,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -788,7 +806,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -797,8 +815,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -818,10 +837,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -829,9 +848,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -841,12 +860,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -857,8 +876,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -879,10 +899,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -890,15 +910,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -908,12 +928,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -926,8 +946,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -946,10 +967,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -958,7 +979,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -972,9 +993,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -984,12 +1005,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -1002,28 +1023,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -1033,54 +1055,57 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition process_withdrawal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "wd" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "wd" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increase the balance of the withdrawing account.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "wd" |), "address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1097,19 +1122,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1125,21 +1151,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1151,8 +1177,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1166,19 +1193,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1195,19 +1223,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1226,14 +1255,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1246,18 +1275,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1266,7 +1295,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1274,7 +1303,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1287,10 +1316,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1298,21 +1327,22 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_transient_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "transient_storage"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "transient_storage"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account from transient storage.
     Returns `U256(0)` if the storage key has not been set previously.
@@ -1332,9 +1362,9 @@ Definition get_transient_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "transient_storage" |), "_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1343,14 +1373,14 @@ Definition get_transient_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1365,30 +1395,31 @@ Definition get_transient_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_transient_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "transient_storage"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "transient_storage"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -1406,9 +1437,9 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "transient_storage" |), "_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1417,7 +1448,7 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1425,17 +1456,17 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "transient_storage" |), "_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1443,11 +1474,11 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -1455,14 +1486,14 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "transient_storage" |), "_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "transient_storage" |), "_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -1472,8 +1503,9 @@ Definition set_transient_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_touched_empty_accounts : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "touched_accounts" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "touched_accounts" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Destroy all touched accounts that are empty.
     Parameters
@@ -1485,27 +1517,27 @@ Definition destroy_touched_empty_accounts : Value.t -> Value.t -> M :=
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_name (| globals, "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_name (| globals, locals_stack, "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_name (| globals, "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_name (| globals, locals_stack, "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/cancun/transactions.v b/CoqOfPython/ethereum/cancun/transactions.v
index e5e186a..960718c 100644
--- a/CoqOfPython/ethereum/cancun/transactions.v
+++ b/CoqOfPython/ethereum/cancun/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.transactions".
+Definition globals : Globals.t := "ethereum.cancun.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,14 +111,15 @@ Definition BlobTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |); M.get_name (| globals, "BlobTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |); M.get_name (| globals, locals_stack, "BlobTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -124,17 +127,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -143,10 +146,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -156,9 +159,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -171,10 +174,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -184,9 +187,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -199,10 +202,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "tx" |);
-                        M.get_name (| globals, "BlobTransaction" |)
+                        M.get_name (| globals, locals_stack, "tx" |);
+                        M.get_name (| globals, locals_stack, "BlobTransaction" |)
                       ],
                       make_dict []
                     |),
@@ -212,9 +215,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                       BinOp.add (|
                         Constant.bytes "03",
                         M.call (|
-                          M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                           make_list [
-                            M.get_name (| globals, "tx" |)
+                            M.get_name (| globals, locals_stack, "tx" |)
                           ],
                           make_dict []
                         |)
@@ -224,7 +227,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "Exception" |),
+                      M.get_name (| globals, locals_stack, "Exception" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -241,8 +244,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -250,10 +254,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -264,7 +268,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -273,11 +277,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -294,7 +298,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -303,11 +307,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -324,7 +328,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                   M.if_then_else (|
                     Compare.eq (|
                       M.get_subscript (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 0
                       |),
                       Constant.int 3
@@ -333,11 +337,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                   ltac:(M.monadic (
                     let _ := M.return_ (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                         make_list [
-                          M.get_name (| globals, "BlobTransaction" |);
+                          M.get_name (| globals, locals_stack, "BlobTransaction" |);
                           M.slice (|
-                            M.get_name (| globals, "tx" |),
+                            M.get_name (| globals, locals_stack, "tx" |),
                             Constant.int 1,
                             Constant.None_,
                             Constant.None_
@@ -349,7 +353,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                     M.pure Constant.None_
                   )) |) in
                 M.pure Constant.None_
@@ -360,7 +364,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/cancun/trie.v b/CoqOfPython/ethereum/cancun/trie.v
index ef7de86..45253b2 100644
--- a/CoqOfPython/ethereum/cancun/trie.v
+++ b/CoqOfPython/ethereum/cancun/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.trie".
+Definition globals : Globals.t := "ethereum.cancun.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -91,10 +93,10 @@ Axiom ethereum_cancun_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -107,14 +109,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); M.get_name (| globals, "Withdrawal" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); M.get_name (| globals, locals_stack, "Withdrawal" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -124,41 +126,41 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Withdrawal" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Withdrawal" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -196,14 +198,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -227,7 +230,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -243,10 +246,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -255,13 +258,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -270,10 +273,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -282,13 +285,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -297,10 +300,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -309,9 +312,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -319,7 +322,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -336,9 +339,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -348,9 +351,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -359,16 +362,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -378,8 +381,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -389,25 +393,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -419,10 +423,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Withdrawal" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Withdrawal" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -430,13 +434,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -451,27 +455,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -495,8 +499,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -513,14 +518,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -531,8 +536,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -552,8 +558,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -561,14 +567,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -580,18 +586,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -611,10 +618,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -622,21 +629,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -649,11 +657,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -661,12 +669,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -674,7 +682,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -689,9 +697,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -699,8 +707,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -737,7 +746,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -748,9 +757,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -761,13 +770,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -775,15 +784,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -793,20 +802,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -824,7 +833,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -832,13 +841,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -847,15 +856,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -865,20 +874,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -896,9 +905,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -906,8 +915,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -924,14 +934,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -942,26 +952,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -969,17 +979,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -991,9 +1001,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -1001,8 +1011,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1023,9 +1034,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1034,25 +1045,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1060,13 +1071,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1080,9 +1091,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1090,13 +1101,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1104,15 +1115,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1122,22 +1133,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1146,13 +1157,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1173,10 +1185,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1184,14 +1196,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1209,12 +1221,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1227,12 +1239,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1244,18 +1256,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1265,8 +1277,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1290,9 +1303,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1311,12 +1324,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1329,9 +1342,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1342,24 +1355,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1369,8 +1382,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1378,31 +1391,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1417,7 +1430,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1438,7 +1451,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1446,30 +1459,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1489,9 +1502,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1499,7 +1512,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1517,21 +1530,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1539,19 +1552,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1560,8 +1573,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1570,17 +1583,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1593,10 +1606,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/utils/__init__.v b/CoqOfPython/ethereum/cancun/utils/__init__.v
index 3e26e47..79ec750 100644
--- a/CoqOfPython/ethereum/cancun/utils/__init__.v
+++ b/CoqOfPython/ethereum/cancun/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.utils.__init__".
+Definition globals : Globals.t := "ethereum.cancun.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/cancun/utils/address.v b/CoqOfPython/ethereum/cancun/utils/address.v
index c9e2edc..4cc1454 100644
--- a/CoqOfPython/ethereum/cancun/utils/address.v
+++ b/CoqOfPython/ethereum/cancun/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.utils.address".
+Definition globals : Globals.t := "ethereum.cancun.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_cancun_fork_types_imports_Address :
   IsImported globals "ethereum.cancun.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/utils/hexadecimal.v b/CoqOfPython/ethereum/cancun/utils/hexadecimal.v
index 8834108..dd5a681 100644
--- a/CoqOfPython/ethereum/cancun/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/cancun/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.cancun.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_cancun_fork_types_imports_Root :
   IsImported globals "ethereum.cancun.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/cancun/utils/message.v b/CoqOfPython/ethereum/cancun/utils/message.v
index e62d563..b55ae28 100644
--- a/CoqOfPython/ethereum/cancun/utils/message.v
+++ b/CoqOfPython/ethereum/cancun/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.utils.message".
+Definition globals : Globals.t := "ethereum.cancun.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_cancun_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.cancun.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/vm/__init__.v b/CoqOfPython/ethereum/cancun/vm/__init__.v
index 5efb61d..c02cc0a 100644
--- a/CoqOfPython/ethereum/cancun/vm/__init__.v
+++ b/CoqOfPython/ethereum/cancun/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.__init__".
+Definition globals : Globals.t := "ethereum.cancun.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -101,8 +103,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -115,30 +118,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -146,19 +149,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -168,24 +171,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -200,15 +204,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -221,8 +225,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -230,19 +234,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -258,7 +262,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/exceptions.v b/CoqOfPython/ethereum/cancun/vm/exceptions.v
index 42aba40..257d805 100644
--- a/CoqOfPython/ethereum/cancun/vm/exceptions.v
+++ b/CoqOfPython/ethereum/cancun/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.exceptions".
+Definition globals : Globals.t := "ethereum.cancun.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/cancun/vm/gas.v b/CoqOfPython/ethereum/cancun/vm/gas.v
index 8e04e69..e2a9141 100644
--- a/CoqOfPython/ethereum/cancun/vm/gas.v
+++ b/CoqOfPython/ethereum/cancun/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.gas".
+Definition globals : Globals.t := "ethereum.cancun.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -58,7 +60,7 @@ Axiom ethereum_cancun_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -68,7 +70,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -78,7 +80,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -88,7 +90,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -98,7 +100,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -108,7 +110,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -118,7 +120,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -128,7 +130,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -138,7 +140,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -148,7 +150,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -158,7 +160,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -168,7 +170,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -178,7 +180,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -188,7 +190,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -198,7 +200,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -208,7 +210,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -218,7 +220,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -228,7 +230,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -238,7 +240,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -248,7 +250,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -258,7 +260,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -268,7 +270,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -278,7 +280,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -288,7 +290,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -298,7 +300,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -308,7 +310,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -318,7 +320,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -328,7 +330,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -338,7 +340,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -348,7 +350,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -358,7 +360,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -368,7 +370,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -378,7 +380,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -388,7 +390,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -398,7 +400,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -408,7 +410,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -418,7 +420,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -428,7 +430,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -438,7 +440,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -448,7 +450,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -462,7 +464,7 @@ Definition GAS_INIT_CODE_WORD_COST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOBHASH_OPCODE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -472,7 +474,7 @@ Definition GAS_BLOBHASH_OPCODE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_POINT_EVALUATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50000
     ],
@@ -482,7 +484,7 @@ Definition GAS_POINT_EVALUATION : Value.t := M.run ltac:(M.monadic (
 
 Definition TARGET_BLOB_GAS_PER_BLOCK : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U64" |),
+    M.get_name (| globals, locals_stack, "U64" |),
     make_list [
       Constant.int 393216
     ],
@@ -492,7 +494,7 @@ Definition TARGET_BLOB_GAS_PER_BLOCK : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_PER_BLOB : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       BinOp.pow (|
         Constant.int 2,
@@ -505,7 +507,7 @@ Definition GAS_PER_BLOB : Value.t := M.run ltac:(M.monadic (
 
 Definition MIN_BLOB_GASPRICE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -515,7 +517,7 @@ Definition MIN_BLOB_GASPRICE : Value.t := M.run ltac:(M.monadic (
 
 Definition BLOB_GASPRICE_UPDATE_FRACTION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3338477
     ],
@@ -544,8 +546,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -558,13 +561,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -575,22 +578,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -600,8 +603,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -621,9 +625,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -633,15 +637,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -650,16 +654,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -678,7 +683,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -688,7 +693,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -698,12 +703,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -713,14 +718,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -734,9 +739,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -744,20 +749,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -770,8 +775,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -785,16 +790,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -802,9 +807,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -813,13 +818,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -829,10 +834,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -840,8 +845,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -872,13 +878,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -886,32 +892,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -925,18 +931,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -947,15 +953,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -964,8 +970,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -981,9 +988,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
@@ -991,8 +998,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition init_code_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "init_code_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "init_code_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas to be charged for the init code in CREAT*
     opcodes as well as create transactions.
@@ -1011,11 +1019,11 @@ Definition init_code_cost : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BinOp.floor_div (|
         BinOp.mult (|
-          M.get_name (| globals, "GAS_INIT_CODE_WORD_COST" |),
+          M.get_name (| globals, locals_stack, "GAS_INIT_CODE_WORD_COST" |),
           M.call (|
-            M.get_name (| globals, "ceil32" |),
+            M.get_name (| globals, locals_stack, "ceil32" |),
             make_list [
-              M.get_name (| globals, "init_code_length" |)
+              M.get_name (| globals, locals_stack, "init_code_length" |)
             ],
             make_dict []
           |)
@@ -1026,8 +1034,9 @@ Definition init_code_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_excess_blob_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculated the excess blob gas for the current block based
     on the gas used in the parent block.
@@ -1045,22 +1054,22 @@ Definition calculate_excess_blob_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_blob_gas" ,
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "excess_blob_gas" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "blob_gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "excess_blob_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "blob_gas_used" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "parent_blob_gas" |),
-          M.get_name (| globals, "TARGET_BLOB_GAS_PER_BLOCK" |)
+          M.get_name (| globals, locals_stack, "parent_blob_gas" |),
+          M.get_name (| globals, locals_stack, "TARGET_BLOB_GAS_PER_BLOCK" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U64" |),
+            M.get_name (| globals, locals_stack, "U64" |),
             make_list [
               Constant.int 0
             ],
@@ -1072,8 +1081,8 @@ Definition calculate_excess_blob_gas : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.sub (|
-            M.get_name (| globals, "parent_blob_gas" |),
-            M.get_name (| globals, "TARGET_BLOB_GAS_PER_BLOCK" |)
+            M.get_name (| globals, locals_stack, "parent_blob_gas" |),
+            M.get_name (| globals, locals_stack, "TARGET_BLOB_GAS_PER_BLOCK" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1081,8 +1090,9 @@ Definition calculate_excess_blob_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_total_blob_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the total blob gas for a transaction.
 
@@ -1100,10 +1110,10 @@ Definition calculate_total_blob_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "BlobTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "BlobTransaction" |)
           ],
           make_dict []
         |),
@@ -1111,11 +1121,11 @@ Definition calculate_total_blob_gas : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.mult (|
-            M.get_name (| globals, "GAS_PER_BLOB" |),
+            M.get_name (| globals, locals_stack, "GAS_PER_BLOB" |),
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "tx" |), "blob_versioned_hashes" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "blob_versioned_hashes" |)
               ],
               make_dict []
             |)
@@ -1126,7 +1136,7 @@ Definition calculate_total_blob_gas : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -1138,8 +1148,9 @@ Definition calculate_total_blob_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_blob_gas_price : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "excess_blob_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "excess_blob_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the blob gasprice for a block.
 
@@ -1155,17 +1166,17 @@ Definition calculate_blob_gas_price : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "taylor_exponential" |),
+        M.get_name (| globals, locals_stack, "taylor_exponential" |),
         make_list [
-          M.get_name (| globals, "MIN_BLOB_GASPRICE" |);
+          M.get_name (| globals, locals_stack, "MIN_BLOB_GASPRICE" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "excess_blob_gas" |)
+              M.get_name (| globals, locals_stack, "excess_blob_gas" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "BLOB_GASPRICE_UPDATE_FRACTION" |)
+          M.get_name (| globals, locals_stack, "BLOB_GASPRICE_UPDATE_FRACTION" |)
         ],
         make_dict []
       |)
@@ -1173,8 +1184,9 @@ Definition calculate_blob_gas_price : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_data_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "excess_blob_gas"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "excess_blob_gas"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the blob data fee for a transaction.
 
@@ -1193,16 +1205,16 @@ Definition calculate_data_fee : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BinOp.mult (|
         M.call (|
-          M.get_name (| globals, "calculate_total_blob_gas" |),
+          M.get_name (| globals, locals_stack, "calculate_total_blob_gas" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "calculate_blob_gas_price" |),
+          M.get_name (| globals, locals_stack, "calculate_blob_gas_price" |),
           make_list [
-            M.get_name (| globals, "excess_blob_gas" |)
+            M.get_name (| globals, locals_stack, "excess_blob_gas" |)
           ],
           make_dict []
         |)
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/__init__.v b/CoqOfPython/ethereum/cancun/vm/instructions/__init__.v
index 0523587..153a2a3 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/cancun/vm/instructions/arithmetic.v
index dc9d022..841636b 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/bitwise.v b/CoqOfPython/ethereum/cancun/vm/instructions/bitwise.v
index 3a02f86..63df69c 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/block.v b/CoqOfPython/ethereum/cancun/vm/instructions/block.v
index f0c6cb2..7c09d92 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -57,18 +60,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -77,14 +80,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -102,23 +105,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -127,14 +130,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -156,21 +160,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -179,14 +183,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -208,31 +213,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -253,21 +259,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -276,14 +282,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition prev_randao : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the `prev_randao` value onto the stack.
 
@@ -304,21 +311,21 @@ Definition prev_randao : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "prev_randao" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "prev_randao" |)
         ],
         make_dict []
       |)
@@ -327,14 +334,15 @@ Definition prev_randao : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -355,21 +363,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -378,14 +386,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -403,21 +412,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -426,7 +435,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/comparison.v b/CoqOfPython/ethereum/cancun/vm/instructions/comparison.v
index a80ba14..645ec45 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/control_flow.v b/CoqOfPython/ethereum/cancun/vm/instructions/control_flow.v
index ac1ba96..b659a5e 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/environment.v b/CoqOfPython/ethereum/cancun/vm/instructions/environment.v
index ab22c8e..abac4b4 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -82,8 +84,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -95,21 +98,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -118,14 +121,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -138,12 +142,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -155,16 +159,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -172,17 +176,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -191,32 +195,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -229,21 +234,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -252,14 +257,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -271,21 +277,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -294,14 +300,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -313,31 +320,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -351,30 +359,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -385,13 +393,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -400,14 +408,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -419,24 +428,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -448,14 +457,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -471,9 +481,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -481,9 +491,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,9 +501,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -502,12 +512,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -520,76 +530,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -601,24 +612,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -630,14 +641,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -653,9 +665,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -663,9 +675,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -673,9 +685,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -684,12 +696,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -702,76 +714,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -783,21 +796,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -806,14 +819,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -826,12 +840,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,16 +857,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -860,17 +874,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -879,16 +893,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -900,23 +914,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -929,12 +944,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -945,9 +960,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -955,9 +970,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -965,9 +980,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -976,12 +991,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -994,18 +1009,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1015,21 +1030,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1038,22 +1053,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1062,19 +1077,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1082,34 +1097,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1120,24 +1136,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1149,14 +1165,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1168,9 +1185,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1178,9 +1195,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1188,9 +1205,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1199,12 +1216,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1217,108 +1234,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1329,12 +1347,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1346,16 +1364,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1363,17 +1381,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1382,10 +1400,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1394,15 +1412,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1415,12 +1433,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1431,23 +1449,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1459,42 +1478,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1506,21 +1526,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1529,14 +1549,15 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition blob_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the versioned hash at a particular index on to the stack.
 
@@ -1549,18 +1570,18 @@ Definition blob_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOBHASH_OPCODE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOBHASH_OPCODE" |)
     ],
     make_dict []
   |) in
@@ -1568,11 +1589,11 @@ Definition blob_hash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "index" |),
+          M.get_name (| globals, locals_stack, "index" |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "blob_versioned_hashes" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "blob_versioned_hashes" |)
             ],
             make_dict []
           |)
@@ -1582,8 +1603,8 @@ Definition blob_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "blob_hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "blob_versioned_hashes" |),
-            M.get_name (| globals, "index" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "blob_versioned_hashes" |),
+            M.get_name (| globals, locals_stack, "index" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1592,7 +1613,7 @@ Definition blob_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "blob_hash" ,
           M.call (|
-            M.get_name (| globals, "Bytes32" |),
+            M.get_name (| globals, locals_stack, "Bytes32" |),
             make_list [
               BinOp.mult (|
                 Constant.bytes "00",
@@ -1605,13 +1626,13 @@ Definition blob_hash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "blob_hash" |)
+          M.get_name (| globals, locals_stack, "blob_hash" |)
         ],
         make_dict []
       |)
@@ -1620,14 +1641,15 @@ Definition blob_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition blob_base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the blob base fee on to the stack.
 
@@ -1639,31 +1661,31 @@ Definition blob_base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blob_base_fee" ,
       M.call (|
-        M.get_name (| globals, "calculate_blob_gas_price" |),
+        M.get_name (| globals, locals_stack, "calculate_blob_gas_price" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "excess_blob_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "excess_blob_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_name (| globals, "blob_base_fee" |)
+          M.get_name (| globals, locals_stack, "blob_base_fee" |)
         ],
         make_dict []
       |)
@@ -1672,7 +1694,7 @@ Definition blob_base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/keccak.v b/CoqOfPython/ethereum/cancun/vm/instructions/keccak.v
index 03a31d2..4951ae6 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/log.v b/CoqOfPython/ethereum/cancun/vm/instructions/log.v
index cfc4c02..21566ee 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_cancun_vm_stack_imports_pop :
   IsImported globals "ethereum.cancun.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/memory.v b/CoqOfPython/ethereum/cancun/vm/instructions/memory.v
index acd8e09..876eba1 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -52,8 +54,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -68,9 +71,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -79,9 +82,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -92,17 +95,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -115,43 +118,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -166,9 +170,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -176,9 +180,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -186,12 +190,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -203,32 +207,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -237,24 +241,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -267,9 +272,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -277,12 +282,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -294,36 +299,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -337,23 +342,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -365,24 +371,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -394,14 +400,15 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mcopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy the bytes in memory from one location to another.
 
@@ -414,9 +421,9 @@ Definition mcopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "destination" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -424,9 +431,9 @@ Definition mcopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "source" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -434,9 +441,9 @@ Definition mcopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "length" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -445,12 +452,12 @@ Definition mcopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "length" |)
+                M.get_name (| globals, locals_stack, "length" |)
               ],
               make_dict []
             |)
@@ -463,70 +470,70 @@ Definition mcopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "source" |); M.get_name (| globals, "length" |) ];
-            make_tuple [ M.get_name (| globals, "destination" |); M.get_name (| globals, "length" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "source" |); M.get_name (| globals, locals_stack, "length" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "destination" |); M.get_name (| globals, locals_stack, "length" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "source" |);
-          M.get_name (| globals, "length" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "source" |);
+          M.get_name (| globals, locals_stack, "length" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "destination" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "destination" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/stack.v b/CoqOfPython/ethereum/cancun/vm/instructions/stack.v
index aec7b04..6cf72ee 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_cancun_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.cancun.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack. Push zero if num_bytes is zero.
 
@@ -100,16 +104,16 @@ Definition push_n : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "num_bytes" |),
+          M.get_name (| globals, locals_stack, "num_bytes" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
@@ -117,10 +121,10 @@ Definition push_n : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -129,26 +133,26 @@ Definition push_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -160,26 +164,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -195,67 +200,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -275,64 +281,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -340,9 +346,9 @@ Definition push0 : Value.t := M.run ltac:(M.monadic (
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -350,9 +356,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -360,9 +366,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -370,9 +376,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -380,9 +386,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -390,9 +396,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -400,9 +406,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -410,9 +416,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -420,9 +426,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -430,9 +436,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -440,9 +446,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -450,9 +456,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -460,9 +466,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -470,9 +476,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -480,9 +486,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -490,9 +496,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -500,9 +506,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -510,9 +516,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -520,9 +526,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -530,9 +536,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -540,9 +546,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -550,9 +556,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -560,9 +566,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -570,9 +576,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -580,9 +586,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -590,9 +596,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -600,9 +606,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -610,9 +616,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -620,9 +626,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -630,9 +636,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -640,9 +646,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -650,9 +656,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -660,9 +666,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -670,9 +676,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -680,9 +686,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -690,9 +696,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -700,9 +706,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -710,9 +716,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -720,9 +726,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -730,9 +736,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -740,9 +746,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -750,9 +756,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -760,9 +766,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -770,9 +776,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -780,9 +786,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -790,9 +796,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -800,9 +806,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -810,9 +816,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -820,9 +826,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -830,9 +836,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -840,9 +846,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -850,9 +856,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -860,9 +866,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -870,9 +876,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -880,9 +886,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -890,9 +896,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -900,9 +906,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -910,9 +916,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -920,9 +926,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -930,9 +936,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -940,9 +946,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -950,9 +956,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -960,9 +966,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -970,9 +976,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/storage.v b/CoqOfPython/ethereum/cancun/vm/instructions/storage.v
index 04025e4..1043ae7 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -63,8 +65,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -79,9 +82,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -93,16 +96,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -110,17 +113,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -129,33 +132,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -169,9 +173,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -182,32 +186,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -215,11 +219,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -227,7 +231,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -238,22 +242,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -265,13 +269,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -281,7 +285,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -289,7 +293,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -298,8 +302,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -310,7 +314,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -318,8 +322,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -328,18 +332,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -350,11 +354,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -369,12 +373,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -383,11 +387,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -401,8 +405,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -410,20 +414,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -434,16 +438,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -462,41 +466,42 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition tload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     transient storage of the current account.
@@ -509,9 +514,9 @@ Definition tload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -520,43 +525,44 @@ Definition tload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_transient_storage" |),
+        M.get_name (| globals, locals_stack, "get_transient_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "transient_storage" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "transient_storage" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition tstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's transient storage.
     Parameters
@@ -568,9 +574,9 @@ Definition tstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -581,42 +587,42 @@ Definition tstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_transient_storage" |),
+    M.get_name (| globals, locals_stack, "set_transient_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "transient_storage" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "transient_storage" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/instructions/system.v b/CoqOfPython/ethereum/cancun/vm/instructions/system.v
index 07121d5..3ef8d6f 100644
--- a/CoqOfPython/ethereum/cancun/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/cancun/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.cancun.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -111,8 +113,9 @@ Axiom ethereum_cancun_vm_stack_imports_push :
   IsImported globals "ethereum.cancun.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size"; "init_code_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size"; "init_code_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
@@ -120,51 +123,51 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |),
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "MAX_CODE_SIZE" |)
+          M.get_name (| globals, locals_stack, "MAX_CODE_SIZE" |)
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -174,32 +177,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -209,15 +212,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -233,10 +236,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -246,15 +249,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -275,29 +278,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -315,17 +318,17 @@ Definition generic_create : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -333,10 +336,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -344,27 +347,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -377,25 +380,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -407,8 +410,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -420,9 +424,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +434,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +444,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -450,11 +454,11 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -463,12 +467,12 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "init_code_gas" ,
       M.call (|
-        M.get_name (| globals, "init_code_cost" |),
+        M.get_name (| globals, locals_stack, "init_code_cost" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "memory_size" |)
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -477,38 +481,38 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
         |),
-        M.get_name (| globals, "init_code_gas" |)
+        M.get_name (| globals, locals_stack, "init_code_gas" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -517,27 +521,28 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |);
-      M.get_name (| globals, "init_code_gas" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |);
+      M.get_name (| globals, locals_stack, "init_code_gas" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -552,9 +557,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -562,9 +567,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -572,9 +577,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -583,9 +588,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -596,11 +601,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -610,12 +615,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -628,12 +633,12 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "init_code_gas" ,
       M.call (|
-        M.get_name (| globals, "init_code_cost" |),
+        M.get_name (| globals, locals_stack, "init_code_cost" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "memory_size" |)
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -642,46 +647,46 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_CREATE" |),
+            M.get_name (| globals, locals_stack, "GAS_CREATE" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-              M.get_name (| globals, "call_data_words" |)
+              M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+              M.get_name (| globals, locals_stack, "call_data_words" |)
             |)
           |),
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
         |),
-        M.get_name (| globals, "init_code_gas" |)
+        M.get_name (| globals, locals_stack, "init_code_gas" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -690,27 +695,28 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |);
-      M.get_name (| globals, "init_code_gas" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |);
+      M.get_name (| globals, locals_stack, "init_code_gas" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -722,9 +728,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -732,9 +738,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -742,63 +748,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -806,24 +813,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -843,11 +850,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -855,10 +862,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -866,7 +873,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -874,10 +881,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -885,27 +892,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -918,23 +925,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -948,16 +955,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -969,14 +976,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -985,8 +992,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -998,12 +1006,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1014,12 +1022,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1030,9 +1038,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1040,9 +1048,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1050,9 +1058,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1060,9 +1068,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1070,9 +1078,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1080,12 +1088,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1095,28 +1103,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1126,16 +1134,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1143,7 +1151,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1151,7 +1159,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1159,13 +1167,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1173,56 +1181,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1231,25 +1239,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1258,17 +1266,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1278,32 +1286,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1311,14 +1319,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1330,12 +1339,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1346,12 +1355,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1362,9 +1371,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1372,9 +1381,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1382,9 +1391,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1392,9 +1401,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1402,26 +1411,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1431,28 +1440,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1461,13 +1470,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1475,58 +1484,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1535,17 +1544,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1555,32 +1564,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1588,14 +1597,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1607,12 +1617,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1622,28 +1632,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1655,20 +1665,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1681,7 +1691,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1689,43 +1699,43 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
-      M.get_name (| globals, "beneficiary" |);
-      M.get_name (| globals, "originator_balance" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
+      M.get_name (| globals, locals_stack, "originator_balance" |)
     ],
     make_dict []
   |) in
@@ -1733,18 +1743,18 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "originator" |),
-          M.get_field (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |), "created_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_field (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |), "created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1754,9 +1764,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1769,19 +1779,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1791,15 +1801,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1811,12 +1822,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1827,12 +1838,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1843,9 +1854,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1853,9 +1864,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1863,9 +1874,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1873,9 +1884,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1883,12 +1894,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1898,104 +1909,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -2007,12 +2019,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2023,12 +2035,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2039,9 +2051,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2049,9 +2061,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2059,9 +2071,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2069,9 +2081,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2079,12 +2091,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2094,110 +2106,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2209,9 +2222,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2219,9 +2232,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2229,54 +2242,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/interpreter.v b/CoqOfPython/ethereum/cancun/vm/interpreter.v
index c3551ef..cb7f0df 100644
--- a/CoqOfPython/ethereum/cancun/vm/interpreter.v
+++ b/CoqOfPython/ethereum/cancun/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.interpreter".
+Definition globals : Globals.t := "ethereum.cancun.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -128,7 +130,7 @@ Axiom ethereum_cancun_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -151,8 +153,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -174,9 +177,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -188,10 +191,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -199,44 +202,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -250,10 +253,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -266,10 +269,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -278,13 +281,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -294,12 +297,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -316,14 +319,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -331,7 +334,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -339,7 +342,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -351,22 +354,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -376,29 +379,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -406,8 +409,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -424,44 +428,44 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "transient_storage" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "transient_storage" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -469,24 +473,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -494,23 +498,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "transient_storage" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "transient_storage" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -530,13 +535,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -548,18 +553,18 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "transient_storage" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "transient_storage" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -567,10 +572,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -578,12 +583,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -595,10 +600,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -606,14 +611,14 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "transient_storage" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "transient_storage" |)
     ],
     make_dict []
   |) in
@@ -621,23 +626,24 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "transient_storage" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "transient_storage" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -655,14 +661,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -670,13 +676,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/memory.v b/CoqOfPython/ethereum/cancun/vm/memory.v
index 71fb1d2..8c8d7b2 100644
--- a/CoqOfPython/ethereum/cancun/vm/memory.v
+++ b/CoqOfPython/ethereum/cancun/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.memory".
+Definition globals : Globals.t := "ethereum.cancun.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/__init__.v
index dbf6f8a..643851e 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
@@ -117,7 +119,7 @@ Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition POINT_EVALUATION_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x0a"
     ],
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/alt_bn128.v
index ec05c60..53fc9cd 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_cancun_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.cancun.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/blake2f.v
index 9f5c33f..cf7db0e 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_cancun_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.cancun.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ecrecover.v
index e169b9c..399b13b 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_cancun_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.cancun.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/identity.v
index bedd17c..8289b55 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_cancun_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.cancun.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/mapping.v
index e780b97..cb5ae03 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/modexp.v
index ec4e35a..aa48ec1 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/point_evaluation.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/point_evaluation.v
index 4b6a5a2..857f687 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/point_evaluation.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/point_evaluation.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.point_evaluation".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.point_evaluation".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Definition VERSIONED_HASH_VERSION_KZG : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition point_evaluation : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     A pre-compile that verifies a KZG proof which claims that a blob
     (represented by a commitment) evaluates to a given value at a given point.
@@ -70,29 +73,29 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 192
       |);
-      M.get_name (| globals, "KZGProofError" |)
+      M.get_name (| globals, locals_stack, "KZGProofError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "versioned_hash" ,
       M.slice (|
-        M.get_name (| globals, "data" |),
+        M.get_name (| globals, locals_stack, "data" |),
         Constant.None_,
         Constant.int 32,
         Constant.None_
@@ -101,7 +104,7 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.slice (|
-        M.get_name (| globals, "data" |),
+        M.get_name (| globals, locals_stack, "data" |),
         Constant.int 32,
         Constant.int 64,
         Constant.None_
@@ -110,7 +113,7 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.slice (|
-        M.get_name (| globals, "data" |),
+        M.get_name (| globals, locals_stack, "data" |),
         Constant.int 64,
         Constant.int 96,
         Constant.None_
@@ -119,10 +122,10 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "commitment" ,
       M.call (|
-        M.get_name (| globals, "KZGCommitment" |),
+        M.get_name (| globals, locals_stack, "KZGCommitment" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "data" |),
+            M.get_name (| globals, locals_stack, "data" |),
             Constant.int 96,
             Constant.int 144,
             Constant.None_
@@ -134,57 +137,57 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "proof" ,
       M.slice (|
-        M.get_name (| globals, "data" |),
+        M.get_name (| globals, locals_stack, "data" |),
         Constant.int 144,
         Constant.int 192,
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_POINT_EVALUATION" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_POINT_EVALUATION" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "kzg_commitment_to_versioned_hash" |),
+          M.get_name (| globals, locals_stack, "kzg_commitment_to_versioned_hash" |),
           make_list [
-            M.get_name (| globals, "commitment" |)
+            M.get_name (| globals, locals_stack, "commitment" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "versioned_hash" |)
+        M.get_name (| globals, locals_stack, "versioned_hash" |)
       |);
-      M.get_name (| globals, "KZGProofError" |)
+      M.get_name (| globals, locals_stack, "KZGProofError" |)
     ],
     make_dict []
   |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      M.get_name (| globals, "kzg_proof_verification" |);
-      M.get_name (| globals, "KZGProofError" |)
+      M.get_name (| globals, locals_stack, "kzg_proof_verification" |);
+      M.get_name (| globals, locals_stack, "KZGProofError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           BinOp.add (|
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "FIELD_ELEMENTS_PER_BLOB" |)
+                  M.get_name (| globals, locals_stack, "FIELD_ELEMENTS_PER_BLOB" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -193,9 +196,9 @@ Definition point_evaluation : Value.t -> Value.t -> M :=
             |),
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "BLS_MODULUS" |)
+                  M.get_name (| globals, locals_stack, "BLS_MODULUS" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ripemd160.v
index 18c8614..9b8920d 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_cancun_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.cancun.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/sha256.v
index fe7ed42..383000d 100644
--- a/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/cancun/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.cancun.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_cancun_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.cancun.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/cancun/vm/runtime.v b/CoqOfPython/ethereum/cancun/vm/runtime.v
index 5c08753..1b9c307 100644
--- a/CoqOfPython/ethereum/cancun/vm/runtime.v
+++ b/CoqOfPython/ethereum/cancun/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.runtime".
+Definition globals : Globals.t := "ethereum.cancun.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_cancun_vm_instructions_imports_Ops :
   IsImported globals "ethereum.cancun.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/cancun/vm/stack.v b/CoqOfPython/ethereum/cancun/vm/stack.v
index 8c8a63b..d284bd8 100644
--- a/CoqOfPython/ethereum/cancun/vm/stack.v
+++ b/CoqOfPython/ethereum/cancun/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.cancun.vm.stack".
+Definition globals : Globals.t := "ethereum.cancun.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_cancun_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.cancun.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/__init__.v b/CoqOfPython/ethereum/constantinople/__init__.v
index 4727e2a..630e0ed 100644
--- a/CoqOfPython/ethereum/constantinople/__init__.v
+++ b/CoqOfPython/ethereum/constantinople/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.__init__".
+Definition globals : Globals.t := "ethereum.constantinople.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 7280000
     ],
diff --git a/CoqOfPython/ethereum/constantinople/blocks.v b/CoqOfPython/ethereum/constantinople/blocks.v
index e6c6eb3..ffb89c6 100644
--- a/CoqOfPython/ethereum/constantinople/blocks.v
+++ b/CoqOfPython/ethereum/constantinople/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.blocks".
+Definition globals : Globals.t := "ethereum.constantinople.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/constantinople/bloom.v b/CoqOfPython/ethereum/constantinople/bloom.v
index a432ffc..a7f9abc 100644
--- a/CoqOfPython/ethereum/constantinople/bloom.v
+++ b/CoqOfPython/ethereum/constantinople/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.bloom".
+Definition globals : Globals.t := "ethereum.constantinople.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_constantinople_fork_types_imports_Bloom :
   IsImported globals "ethereum.constantinople.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/fork.v b/CoqOfPython/ethereum/constantinople/fork.v
index 06668fb..7459441 100644
--- a/CoqOfPython/ethereum/constantinople/fork.v
+++ b/CoqOfPython/ethereum/constantinople/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.fork".
+Definition globals : Globals.t := "ethereum.constantinople.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_constantinople_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -176,10 +178,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -201,8 +203,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -222,13 +225,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -251,7 +255,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -262,9 +266,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -286,17 +290,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -309,13 +313,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -326,20 +330,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -364,111 +369,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -477,9 +482,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -488,9 +493,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -504,8 +509,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -526,101 +532,101 @@ Definition validate_header : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -629,28 +635,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -676,26 +683,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -703,8 +710,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -722,9 +730,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -732,25 +740,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -759,41 +767,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -817,35 +826,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -869,13 +879,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -890,8 +900,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -934,51 +945,51 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -986,18 +997,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1005,49 +1016,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1056,56 +1067,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1116,8 +1127,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1142,27 +1154,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1171,9 +1183,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1191,46 +1203,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1241,19 +1253,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1262,23 +1274,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1286,16 +1298,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1309,13 +1321,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1330,11 +1342,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1342,88 +1354,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1436,8 +1448,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1466,44 +1479,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1515,19 +1528,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1540,8 +1553,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1569,30 +1583,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1600,98 +1614,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1699,10 +1713,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1710,20 +1724,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1732,10 +1746,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1743,41 +1757,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1785,31 +1799,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1820,20 +1834,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1846,14 +1860,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1865,27 +1879,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1901,13 +1915,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1936,17 +1951,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1961,8 +1976,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1991,14 +2007,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2006,7 +2022,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2014,7 +2030,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2028,9 +2044,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2041,7 +2057,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2054,14 +2070,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2070,8 +2086,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2094,47 +2111,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2143,12 +2160,12 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -2158,18 +2175,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_pre155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |)
+                  M.get_name (| globals, locals_stack, "tx" |)
                 ],
                 make_dict []
               |)
@@ -2181,58 +2198,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 35
                 |),
                 BinOp.mult (|
-                  M.get_name (| globals, "chain_id" |),
+                  M.get_name (| globals, locals_stack, "chain_id" |),
                   Constant.int 2
                 |)
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |);
-                  M.get_name (| globals, "chain_id" |)
+                  M.get_name (| globals, locals_stack, "tx" |);
+                  M.get_name (| globals, locals_stack, "chain_id" |)
                 ],
                 make_dict []
               |)
@@ -2244,13 +2261,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2265,8 +2282,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2282,12 +2300,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2298,8 +2316,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2317,19 +2336,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2345,8 +2364,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2380,12 +2400,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2396,8 +2416,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2428,18 +2449,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2456,10 +2477,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2476,8 +2497,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2495,8 +2516,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2540,21 +2562,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -2564,11 +2586,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2586,13 +2608,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2601,13 +2623,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -2618,7 +2640,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2628,7 +2650,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2638,13 +2660,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/constantinople/fork_types.v b/CoqOfPython/ethereum/constantinople/fork_types.v
index 351e1ef..b0fd4d6 100644
--- a/CoqOfPython/ethereum/constantinople/fork_types.v
+++ b/CoqOfPython/ethereum/constantinople/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.fork_types".
+Definition globals : Globals.t := "ethereum.constantinople.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/constantinople/state.v b/CoqOfPython/ethereum/constantinople/state.v
index 15a1a6d..c3780db 100644
--- a/CoqOfPython/ethereum/constantinople/state.v
+++ b/CoqOfPython/ethereum/constantinople/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.state".
+Definition globals : Globals.t := "ethereum.constantinople.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,8 +710,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -714,10 +732,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -725,9 +743,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -737,12 +755,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -753,8 +771,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -775,10 +794,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -786,15 +805,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -804,12 +823,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -822,8 +841,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -842,10 +862,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -854,7 +874,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -868,9 +888,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -880,12 +900,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -898,28 +918,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -929,36 +950,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -975,19 +998,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1003,21 +1027,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1029,8 +1053,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1044,19 +1069,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1073,19 +1099,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1100,11 +1127,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/constantinople/transactions.v b/CoqOfPython/ethereum/constantinople/transactions.v
index e2158f5..c4232b6 100644
--- a/CoqOfPython/ethereum/constantinople/transactions.v
+++ b/CoqOfPython/ethereum/constantinople/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.transactions".
+Definition globals : Globals.t := "ethereum.constantinople.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/constantinople/trie.v b/CoqOfPython/ethereum/constantinople/trie.v
index 18f9155..61ed486 100644
--- a/CoqOfPython/ethereum/constantinople/trie.v
+++ b/CoqOfPython/ethereum/constantinople/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.trie".
+Definition globals : Globals.t := "ethereum.constantinople.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_constantinople_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/utils/__init__.v b/CoqOfPython/ethereum/constantinople/utils/__init__.v
index e5396b1..4a1852f 100644
--- a/CoqOfPython/ethereum/constantinople/utils/__init__.v
+++ b/CoqOfPython/ethereum/constantinople/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.utils.__init__".
+Definition globals : Globals.t := "ethereum.constantinople.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/constantinople/utils/address.v b/CoqOfPython/ethereum/constantinople/utils/address.v
index a23e9b8..d255ebe 100644
--- a/CoqOfPython/ethereum/constantinople/utils/address.v
+++ b/CoqOfPython/ethereum/constantinople/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.utils.address".
+Definition globals : Globals.t := "ethereum.constantinople.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_constantinople_fork_types_imports_Address :
   IsImported globals "ethereum.constantinople.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/utils/hexadecimal.v b/CoqOfPython/ethereum/constantinople/utils/hexadecimal.v
index 6eae082..04eb76a 100644
--- a/CoqOfPython/ethereum/constantinople/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/constantinople/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.constantinople.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_constantinople_fork_types_imports_Root :
   IsImported globals "ethereum.constantinople.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/constantinople/utils/message.v b/CoqOfPython/ethereum/constantinople/utils/message.v
index 202ca4d..6c0733c 100644
--- a/CoqOfPython/ethereum/constantinople/utils/message.v
+++ b/CoqOfPython/ethereum/constantinople/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.utils.message".
+Definition globals : Globals.t := "ethereum.constantinople.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_constantinople_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.constantinople.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -85,10 +88,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -97,20 +100,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -124,7 +127,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -133,7 +136,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -142,10 +145,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -153,19 +156,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -174,14 +177,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -192,7 +195,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -204,7 +207,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/vm/__init__.v b/CoqOfPython/ethereum/constantinople/vm/__init__.v
index 73a0539..c15b0e0 100644
--- a/CoqOfPython/ethereum/constantinople/vm/__init__.v
+++ b/CoqOfPython/ethereum/constantinople/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.__init__".
+Definition globals : Globals.t := "ethereum.constantinople.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -93,8 +95,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -107,30 +110,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -138,19 +141,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -162,8 +165,9 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -178,15 +182,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -199,8 +203,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -208,19 +212,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -236,7 +240,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/exceptions.v b/CoqOfPython/ethereum/constantinople/vm/exceptions.v
index 6a2283c..e9b6a3e 100644
--- a/CoqOfPython/ethereum/constantinople/vm/exceptions.v
+++ b/CoqOfPython/ethereum/constantinople/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.exceptions".
+Definition globals : Globals.t := "ethereum.constantinople.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/constantinople/vm/gas.v b/CoqOfPython/ethereum/constantinople/vm/gas.v
index 7a776c8..a06b70c 100644
--- a/CoqOfPython/ethereum/constantinople/vm/gas.v
+++ b/CoqOfPython/ethereum/constantinople/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.gas".
+Definition globals : Globals.t := "ethereum.constantinople.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_constantinople_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 400
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -436,7 +438,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -446,7 +448,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 400
     ],
@@ -475,8 +477,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -489,13 +492,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -506,22 +509,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -531,8 +534,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -552,9 +556,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -564,15 +568,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -581,16 +585,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,7 +624,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -629,12 +634,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -644,14 +649,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -665,9 +670,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -675,20 +680,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -701,8 +706,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -716,16 +721,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -733,9 +738,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -744,13 +749,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -760,10 +765,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -771,8 +776,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -803,13 +809,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -817,32 +823,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -856,18 +862,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -878,15 +884,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -895,8 +901,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -912,9 +919,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/__init__.v b/CoqOfPython/ethereum/constantinople/vm/instructions/__init__.v
index b8c6731..1debf2b 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/constantinople/vm/instructions/arithmetic.v
index 3e3a445..e315e63 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/bitwise.v b/CoqOfPython/ethereum/constantinople/vm/instructions/bitwise.v
index 76a9113..c0984ab 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/block.v b/CoqOfPython/ethereum/constantinople/vm/instructions/block.v
index 5481330..ddc60b7 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/comparison.v b/CoqOfPython/ethereum/constantinople/vm/instructions/comparison.v
index 50cbb7f..f4c2799 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/control_flow.v b/CoqOfPython/ethereum/constantinople/vm/instructions/control_flow.v
index 4b37436..4363bee 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/environment.v b/CoqOfPython/ethereum/constantinople/vm/instructions/environment.v
index e6edba3..6d28976 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -146,42 +150,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -194,21 +199,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -217,14 +222,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -236,21 +242,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -259,14 +265,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -278,31 +285,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -316,30 +324,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -350,13 +358,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -365,14 +373,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -384,24 +393,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -413,14 +422,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -436,9 +446,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -446,9 +456,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -456,9 +466,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -467,12 +477,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -485,76 +495,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -566,24 +577,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -595,14 +606,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -618,9 +630,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -628,9 +640,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -638,9 +650,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -649,12 +661,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -667,76 +679,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -748,21 +761,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -771,14 +784,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -791,12 +805,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -805,26 +819,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -836,23 +850,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -865,12 +880,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -881,9 +896,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -891,9 +906,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -901,9 +916,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -912,12 +927,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -930,52 +945,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -983,34 +998,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1021,24 +1037,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1050,14 +1066,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1069,9 +1086,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1079,9 +1096,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1089,9 +1106,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1100,12 +1117,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1118,108 +1135,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1230,12 +1248,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1244,20 +1262,20 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_CODE_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_CODE_HASH" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1266,15 +1284,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1287,12 +1305,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1303,16 +1321,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/keccak.v b/CoqOfPython/ethereum/constantinople/vm/instructions/keccak.v
index 8e00e8f..c5502bf 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/log.v b/CoqOfPython/ethereum/constantinople/vm/instructions/log.v
index 51269e5..b0555a1 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_constantinople_vm_stack_imports_pop :
   IsImported globals "ethereum.constantinople.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/memory.v b/CoqOfPython/ethereum/constantinople/vm/instructions/memory.v
index 9b9ada6..627e26f 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/stack.v b/CoqOfPython/ethereum/constantinople/vm/instructions/stack.v
index a87c0aa..a6d509e 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_constantinople_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.constantinople.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/storage.v b/CoqOfPython/ethereum/constantinople/vm/instructions/storage.v
index 95bb7fb..3a891f8 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -48,8 +50,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -64,9 +67,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -75,43 +78,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -125,9 +129,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -138,9 +142,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -148,11 +152,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -162,12 +166,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -176,14 +180,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -192,12 +196,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -206,8 +210,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -215,34 +219,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/instructions/system.v b/CoqOfPython/ethereum/constantinople/vm/instructions/system.v
index d27c09f..6e22c0a 100644
--- a/CoqOfPython/ethereum/constantinople/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/constantinople/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.constantinople.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,8 +107,9 @@ Axiom ethereum_constantinople_vm_stack_imports_push :
   IsImported globals "ethereum.constantinople.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
@@ -114,12 +117,12 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -129,32 +132,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -164,15 +167,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -188,10 +191,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -201,15 +204,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -230,29 +233,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -272,27 +275,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -300,10 +303,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -311,27 +314,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -344,25 +347,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -374,8 +377,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -387,9 +391,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,9 +401,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -407,9 +411,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -417,46 +421,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -465,26 +469,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -499,9 +504,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -509,9 +514,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -519,9 +524,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -530,9 +535,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -543,11 +548,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -557,12 +562,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -573,43 +578,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -618,26 +623,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -649,9 +655,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -659,9 +665,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -669,63 +675,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -733,24 +740,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -770,11 +777,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -782,10 +789,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -793,7 +800,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -801,10 +808,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -812,27 +819,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -845,23 +852,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -875,16 +882,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -896,14 +903,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -912,8 +919,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -925,12 +933,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -941,12 +949,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -957,9 +965,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -967,9 +975,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -977,9 +985,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -987,9 +995,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -997,9 +1005,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1007,12 +1015,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1024,15 +1032,15 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             M.call (|
-              M.get_name (| globals, "is_account_alive" |),
+              M.get_name (| globals, locals_stack, "is_account_alive" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "to" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "to" |)
               ],
               make_dict []
             |)
@@ -1041,7 +1049,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1049,7 +1057,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1057,13 +1065,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1071,56 +1079,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1129,25 +1137,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1156,17 +1164,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1176,32 +1184,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1209,14 +1217,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1228,12 +1237,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1244,12 +1253,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1260,9 +1269,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1270,9 +1279,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1280,9 +1289,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1290,9 +1299,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1300,26 +1309,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1330,13 +1339,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1344,58 +1353,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1404,17 +1413,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1424,32 +1433,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1457,14 +1466,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1476,12 +1486,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1491,27 +1501,27 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1524,7 +1534,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1533,33 +1543,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1571,15 +1581,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1587,28 +1597,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1616,33 +1626,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1652,9 +1662,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1662,19 +1672,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1684,15 +1694,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1704,12 +1715,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1720,12 +1731,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1736,9 +1747,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1746,9 +1757,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1756,9 +1767,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1766,9 +1777,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1776,12 +1787,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1790,76 +1801,77 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1871,12 +1883,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1887,12 +1899,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1903,9 +1915,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1913,9 +1925,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1923,9 +1935,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1933,9 +1945,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1943,12 +1955,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1957,82 +1969,83 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2044,9 +2057,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2054,9 +2067,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2064,54 +2077,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/interpreter.v b/CoqOfPython/ethereum/constantinople/vm/interpreter.v
index b589da7..61036bd 100644
--- a/CoqOfPython/ethereum/constantinople/vm/interpreter.v
+++ b/CoqOfPython/ethereum/constantinople/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.interpreter".
+Definition globals : Globals.t := "ethereum.constantinople.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -122,7 +124,7 @@ Axiom ethereum_constantinople_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -145,8 +147,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -168,9 +171,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -182,10 +185,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -193,44 +196,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -244,10 +247,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -260,10 +263,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -272,13 +275,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -288,12 +291,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -310,14 +313,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -325,7 +328,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -333,7 +336,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -345,48 +348,48 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -394,8 +397,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -412,35 +416,35 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -448,24 +452,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -473,22 +477,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -508,13 +513,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -526,17 +531,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -544,10 +549,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -555,12 +560,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -572,10 +577,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -583,13 +588,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -597,22 +602,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -630,14 +636,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -645,13 +651,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/memory.v b/CoqOfPython/ethereum/constantinople/vm/memory.v
index f8c1898..0c92e48 100644
--- a/CoqOfPython/ethereum/constantinople/vm/memory.v
+++ b/CoqOfPython/ethereum/constantinople/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.memory".
+Definition globals : Globals.t := "ethereum.constantinople.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/__init__.v
index 028d559..3506d9b 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/alt_bn128.v
index 35d5ffd..38dc21f 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_constantinople_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.constantinople.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 500
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 40000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 80000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ecrecover.v
index 3738033..2f6ff0d 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_constantinople_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.constantinople.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/identity.v
index f7e428a..7f3e322 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_constantinople_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.constantinople.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/mapping.v
index 90f0895..9fa87c5 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/modexp.v
index 8bbf71b..1b10eee 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,7 +37,7 @@ Axiom ethereum_constantinople_vm_memory_imports_buffer_read :
 
 Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -44,34 +46,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -87,21 +90,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -117,21 +120,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -148,36 +151,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -192,7 +195,7 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "exp_length" |),
+          M.get_name (| globals, locals_stack, "exp_length" |),
           Constant.int 32
         |),
       (* then *)
@@ -200,15 +203,15 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   Constant.int 0;
                   BinOp.sub (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                       make_list [],
                       make_dict []
                     |),
@@ -227,16 +230,16 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               BinOp.add (|
                 BinOp.mult (|
                   Constant.int 8,
                   BinOp.sub (|
                     M.call (|
-                      M.get_name (| globals, "int" |),
+                      M.get_name (| globals, locals_stack, "int" |),
                       make_list [
-                        M.get_name (| globals, "exp_length" |)
+                        M.get_name (| globals, locals_stack, "exp_length" |)
                       ],
                       make_dict []
                     |),
@@ -244,12 +247,12 @@ Definition modexp : Value.t -> Value.t -> M :=
                   |)
                 |),
                 M.call (|
-                  M.get_name (| globals, "max" |),
+                  M.get_name (| globals, locals_stack, "max" |),
                   make_list [
                     Constant.int 0;
                     BinOp.sub (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                         make_list [],
                         make_dict []
                       |),
@@ -266,22 +269,22 @@ Definition modexp : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.floor_div (|
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "get_mult_complexity" |),
+            M.get_name (| globals, locals_stack, "get_mult_complexity" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "max" |),
+                    M.get_name (| globals, locals_stack, "max" |),
                     make_list [
-                      M.get_name (| globals, "base_length" |);
-                      M.get_name (| globals, "modulus_length" |)
+                      M.get_name (| globals, locals_stack, "base_length" |);
+                      M.get_name (| globals, locals_stack, "modulus_length" |)
                     ],
                     make_dict []
                   |)
@@ -292,11 +295,11 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "adjusted_exp_length" |);
+              M.get_name (| globals, locals_stack, "adjusted_exp_length" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 1
                 ],
@@ -306,7 +309,7 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |)
         |),
-        M.get_name (| globals, "GQUADDIVISOR" |)
+        M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
       |)
     ],
     make_dict []
@@ -316,12 +319,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -329,9 +332,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -347,20 +350,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -371,14 +374,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -389,21 +392,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -415,39 +418,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -455,7 +458,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -466,8 +469,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_mult_complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing Karatsuba multiplication.
     " in
@@ -475,14 +479,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 64
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.pow (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 2
           |)
         |) in
@@ -493,7 +497,7 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "x" |),
+              M.get_name (| globals, locals_stack, "x" |),
               Constant.int 1024
             |),
           (* then *)
@@ -503,14 +507,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 4
                   |),
                   BinOp.mult (|
                     Constant.int 96,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 3072
@@ -524,14 +528,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 16
                   |),
                   BinOp.mult (|
                     Constant.int 480,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 199680
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ripemd160.v
index 9077c68..afa96a2 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_constantinople_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.constantinople.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/sha256.v
index 5e11ce8..d5c505c 100644
--- a/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/constantinople/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.constantinople.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_constantinople_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.constantinople.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/constantinople/vm/runtime.v b/CoqOfPython/ethereum/constantinople/vm/runtime.v
index f830abe..4afd430 100644
--- a/CoqOfPython/ethereum/constantinople/vm/runtime.v
+++ b/CoqOfPython/ethereum/constantinople/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.runtime".
+Definition globals : Globals.t := "ethereum.constantinople.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_constantinople_vm_instructions_imports_Ops :
   IsImported globals "ethereum.constantinople.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/constantinople/vm/stack.v b/CoqOfPython/ethereum/constantinople/vm/stack.v
index afbe789..efd76ba 100644
--- a/CoqOfPython/ethereum/constantinople/vm/stack.v
+++ b/CoqOfPython/ethereum/constantinople/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.constantinople.vm.stack".
+Definition globals : Globals.t := "ethereum.constantinople.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_constantinople_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.constantinople.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/crypto/__init__.v b/CoqOfPython/ethereum/crypto/__init__.v
index d20cfb4..5d03d2a 100644
--- a/CoqOfPython/ethereum/crypto/__init__.v
+++ b/CoqOfPython/ethereum/crypto/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.__init__".
+Definition globals : Globals.t := "ethereum.crypto.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/crypto/alt_bn128.v b/CoqOfPython/ethereum/crypto/alt_bn128.v
index bc2b4ac..beec945 100644
--- a/CoqOfPython/ethereum/crypto/alt_bn128.v
+++ b/CoqOfPython/ethereum/crypto/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.alt_bn128".
+Definition globals : Globals.t := "ethereum.crypto.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -93,8 +95,9 @@ Definition BNF12 : Value.t :=
     [
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Multiplication special cased for BNF12.
         " in
@@ -109,9 +112,9 @@ Definition BNF12 : Value.t :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 12
       ],
@@ -120,9 +123,9 @@ Definition BNF12 : Value.t :=
               ltac:(M.monadic (
                 let _ :=
                   M.for_ (|
-                    M.get_name (| globals, "j" |),
+                    M.get_name (| globals, locals_stack, "j" |),
                     M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 12
       ],
@@ -132,20 +135,20 @@ Definition BNF12 : Value.t :=
                       let _ := M.assign_op (|
                         BinOp.add,
                         M.get_subscript (|
-    M.get_name (| globals, "mul" |),
+    M.get_name (| globals, locals_stack, "mul" |),
     BinOp.add (|
-      M.get_name (| globals, "i" |),
-      M.get_name (| globals, "j" |)
+      M.get_name (| globals, locals_stack, "i" |),
+      M.get_name (| globals, locals_stack, "j" |)
     |)
   |),
                         BinOp.mult (|
     M.get_subscript (|
-      M.get_name (| globals, "self" |),
-      M.get_name (| globals, "i" |)
+      M.get_name (| globals, locals_stack, "self" |),
+      M.get_name (| globals, locals_stack, "i" |)
     |),
     M.get_subscript (|
-      M.get_name (| globals, "right" |),
-      M.get_name (| globals, "j" |)
+      M.get_name (| globals, locals_stack, "right" |),
+      M.get_name (| globals, locals_stack, "j" |)
     |)
   |)
                       |) in
@@ -163,9 +166,9 @@ Definition BNF12 : Value.t :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 22;
         Constant.int 11;
@@ -177,16 +180,16 @@ Definition BNF12 : Value.t :=
                 let _ := M.assign_op (|
                   BinOp.sub,
                   M.get_subscript (|
-    M.get_name (| globals, "mul" |),
+    M.get_name (| globals, locals_stack, "mul" |),
     BinOp.sub (|
-      M.get_name (| globals, "i" |),
+      M.get_name (| globals, locals_stack, "i" |),
       Constant.int 6
     |)
   |),
                   BinOp.mult (|
     M.get_subscript (|
-      M.get_name (| globals, "mul" |),
-      M.get_name (| globals, "i" |)
+      M.get_name (| globals, locals_stack, "mul" |),
+      M.get_name (| globals, locals_stack, "i" |)
     |),
     UnOp.sub (| Constant.int 18 |)
   |)
@@ -194,16 +197,16 @@ Definition BNF12 : Value.t :=
                 let _ := M.assign_op (|
                   BinOp.sub,
                   M.get_subscript (|
-    M.get_name (| globals, "mul" |),
+    M.get_name (| globals, locals_stack, "mul" |),
     BinOp.sub (|
-      M.get_name (| globals, "i" |),
+      M.get_name (| globals, locals_stack, "i" |),
       Constant.int 12
     |)
   |),
                   BinOp.mult (|
     M.get_subscript (|
-      M.get_name (| globals, "mul" |),
-      M.get_name (| globals, "i" |)
+      M.get_name (| globals, locals_stack, "mul" |),
+      M.get_name (| globals, locals_stack, "i" |)
     |),
     Constant.int 82
   |)
@@ -216,11 +219,11 @@ Definition BNF12 : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "BNF12" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "BNF12" |);
+                M.get_name (| globals, locals_stack, "BNF12" |);
                 M.slice (|
-                  M.get_name (| globals, "mul" |),
+                  M.get_name (| globals, locals_stack, "mul" |),
                   Constant.None_,
                   Constant.int 12,
                   Constant.None_
@@ -259,18 +262,19 @@ Definition BNP12 : Value.t :=
     ].
 
 Definition bnf2_to_bnf12 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Lift a field element in `BNF2` to `BNF12`.
     " in
     let _ := M.return_ (|
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
           make_list [
             M.get_subscript (|
-              M.get_name (| globals, "x" |),
+              M.get_name (| globals, locals_stack, "x" |),
               Constant.int 0
             |)
           ],
@@ -278,19 +282,19 @@ Definition bnf2_to_bnf12 : Value.t -> Value.t -> M :=
         |),
         BinOp.mult (|
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               M.get_subscript (|
-                M.get_name (| globals, "x" |),
+                M.get_name (| globals, locals_stack, "x" |),
                 Constant.int 1
               |)
             ],
             make_dict []
           |),
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "i_plus_9" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "i_plus_9" |),
             M.call (|
-              M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
               make_list [
                 Constant.int 9
               ],
@@ -303,22 +307,23 @@ Definition bnf2_to_bnf12 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bnp_to_bnp12 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "p" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "p" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Lift a point from `BNP` to `BNP12`.
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BNP12" |),
+        M.get_name (| globals, locals_stack, "BNP12" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "p" |), "x" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |)
                 ],
                 make_dict []
               |)
@@ -326,12 +331,12 @@ Definition bnp_to_bnp12 : Value.t -> Value.t -> M :=
             make_dict []
           |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "p" |), "y" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |)
                 ],
                 make_dict []
               |)
@@ -345,38 +350,39 @@ Definition bnp_to_bnp12 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition twist : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "p" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "p" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Apply to twist to change variables from the curve `BNP2` to `BNP12`.
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BNP12" |),
+        M.get_name (| globals, locals_stack, "BNP12" |),
         make_list [
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "bnf2_to_bnf12" |),
+              M.get_name (| globals, locals_stack, "bnf2_to_bnf12" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "p" |), "x" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |)
               ],
               make_dict []
             |),
             BinOp.pow (|
-              M.get_field (| M.get_name (| globals, "BNF12" |), "w" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "w" |),
               Constant.int 2
             |)
           |);
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "bnf2_to_bnf12" |),
+              M.get_name (| globals, locals_stack, "bnf2_to_bnf12" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "p" |), "y" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |)
               ],
               make_dict []
             |),
             BinOp.pow (|
-              M.get_field (| M.get_name (| globals, "BNF12" |), "w" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "w" |),
               Constant.int 3
             |)
           |)
@@ -387,8 +393,9 @@ Definition twist : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition linefunc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "p1"; "p2"; "t" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "p1"; "p2"; "t" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Evaluate the function defining the line between points `p1` and `p2` at the
     point `t`. The mathematical significance of this function is that is has
@@ -402,8 +409,8 @@ Definition linefunc : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "p1" |), "x" |),
-          M.get_field (| M.get_name (| globals, "p2" |), "x" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p2" |), "x" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -411,27 +418,27 @@ Definition linefunc : Value.t -> Value.t -> M :=
           "lam" ,
           BinOp.div (|
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "p2" |), "y" |),
-              M.get_field (| M.get_name (| globals, "p1" |), "y" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "p2" |), "y" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "y" |)
             |),
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "p2" |), "x" |),
-              M.get_field (| M.get_name (| globals, "p1" |), "x" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "p2" |), "x" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |)
             |)
           |)
         |) in
         let _ := M.return_ (|
           BinOp.sub (|
             BinOp.mult (|
-              M.get_name (| globals, "lam" |),
+              M.get_name (| globals, locals_stack, "lam" |),
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "t" |), "x" |),
-                M.get_field (| M.get_name (| globals, "p1" |), "x" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "t" |), "x" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |)
               |)
             |),
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "t" |), "y" |),
-              M.get_field (| M.get_name (| globals, "p1" |), "y" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "t" |), "y" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "y" |)
             |)
           |)
         |) in
@@ -442,8 +449,8 @@ Definition linefunc : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "p1" |), "y" |),
-              M.get_field (| M.get_name (| globals, "p2" |), "y" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "y" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "p2" |), "y" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -452,41 +459,41 @@ Definition linefunc : Value.t -> Value.t -> M :=
               BinOp.div (|
                 BinOp.mult (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
                     make_list [
                       Constant.int 3
                     ],
                     make_dict []
                   |),
                   BinOp.pow (|
-                    M.get_field (| M.get_name (| globals, "p1" |), "x" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |),
                     Constant.int 2
                   |)
                 |),
                 BinOp.mult (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
                     make_list [
                       Constant.int 2
                     ],
                     make_dict []
                   |),
-                  M.get_field (| M.get_name (| globals, "p1" |), "y" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "y" |)
                 |)
               |)
             |) in
             let _ := M.return_ (|
               BinOp.sub (|
                 BinOp.mult (|
-                  M.get_name (| globals, "lam" |),
+                  M.get_name (| globals, locals_stack, "lam" |),
                   BinOp.sub (|
-                    M.get_field (| M.get_name (| globals, "t" |), "x" |),
-                    M.get_field (| M.get_name (| globals, "p1" |), "x" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "t" |), "x" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |)
                   |)
                 |),
                 BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "t" |), "y" |),
-                  M.get_field (| M.get_name (| globals, "p1" |), "y" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "t" |), "y" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "y" |)
                 |)
               |)
             |) in
@@ -495,8 +502,8 @@ Definition linefunc : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.return_ (|
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "t" |), "x" |),
-                M.get_field (| M.get_name (| globals, "p1" |), "x" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "t" |), "x" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "p1" |), "x" |)
               |)
             |) in
             M.pure Constant.None_
@@ -506,8 +513,9 @@ Definition linefunc : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition miller_loop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "q"; "p" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "q"; "p" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The core of the pairing algorithm.
     " in
@@ -516,18 +524,18 @@ Definition miller_loop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "p" |),
+            M.get_name (| globals, locals_stack, "p" |),
             M.call (|
-              M.get_field (| M.get_name (| globals, "BNP12" |), "point_at_infinity" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "BNP12" |), "point_at_infinity" |),
               make_list [],
               make_dict []
             |)
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "q" |),
+              M.get_name (| globals, locals_stack, "q" |),
               M.call (|
-                M.get_field (| M.get_name (| globals, "BNP12" |), "point_at_infinity" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "BNP12" |), "point_at_infinity" |),
                 make_list [],
                 make_dict []
               |)
@@ -538,7 +546,7 @@ Definition miller_loop : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -552,12 +560,12 @@ Definition miller_loop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "r" ,
-      M.get_name (| globals, "q" |)
+      M.get_name (| globals, locals_stack, "q" |)
     |) in
     let _ := M.assign_local (|
       "f" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -566,11 +574,11 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "ATE_PAIRING_COUNT_BITS" |);
+        M.get_name (| globals, locals_stack, "ATE_PAIRING_COUNT_BITS" |);
         UnOp.sub (| Constant.int 1 |);
         UnOp.sub (| Constant.int 1 |)
       ],
@@ -581,15 +589,15 @@ Definition miller_loop : Value.t -> Value.t -> M :=
             "f" ,
             BinOp.mult (|
               BinOp.mult (|
-                M.get_name (| globals, "f" |),
-                M.get_name (| globals, "f" |)
+                M.get_name (| globals, locals_stack, "f" |),
+                M.get_name (| globals, locals_stack, "f" |)
               |),
               M.call (|
-                M.get_name (| globals, "linefunc" |),
+                M.get_name (| globals, locals_stack, "linefunc" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "p" |)
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "p" |)
                 ],
                 make_dict []
               |)
@@ -598,7 +606,7 @@ Definition miller_loop : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "r" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "r" |), "double" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "r" |), "double" |),
               make_list [],
               make_dict []
             |)
@@ -608,12 +616,12 @@ Definition miller_loop : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BinOp.bit_and (|
                 BinOp.sub (|
-                  M.get_name (| globals, "ATE_PAIRING_COUNT" |),
+                  M.get_name (| globals, locals_stack, "ATE_PAIRING_COUNT" |),
                   Constant.int 1
                 |),
                 BinOp.pow (|
                   Constant.int 2,
-                  M.get_name (| globals, "i" |)
+                  M.get_name (| globals, locals_stack, "i" |)
                 |)
               |),
             (* then *)
@@ -621,13 +629,13 @@ Definition miller_loop : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "f" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "f" |),
+                  M.get_name (| globals, locals_stack, "f" |),
                   M.call (|
-                    M.get_name (| globals, "linefunc" |),
+                    M.get_name (| globals, locals_stack, "linefunc" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -636,8 +644,8 @@ Definition miller_loop : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "r" ,
                 BinOp.add (|
-                  M.get_name (| globals, "r" |),
-                  M.get_name (| globals, "q" |)
+                  M.get_name (| globals, locals_stack, "r" |),
+                  M.get_name (| globals, locals_stack, "q" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -652,12 +660,12 @@ Definition miller_loop : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.assert (| Compare.eq (|
-    M.get_name (| globals, "r" |),
+    M.get_name (| globals, locals_stack, "r" |),
     M.call (|
-      M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
       make_list [
         BinOp.sub (|
-          M.get_name (| globals, "ATE_PAIRING_COUNT" |),
+          M.get_name (| globals, locals_stack, "ATE_PAIRING_COUNT" |),
           Constant.int 1
         |)
       ],
@@ -667,15 +675,15 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "q1" ,
       M.call (|
-        M.get_name (| globals, "BNP12" |),
+        M.get_name (| globals, locals_stack, "BNP12" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "q" |), "x" |), "frobenius" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "q" |), "x" |), "frobenius" |),
             make_list [],
             make_dict []
           |);
           M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "q" |), "y" |), "frobenius" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "q" |), "y" |), "frobenius" |),
             make_list [],
             make_dict []
           |)
@@ -686,15 +694,15 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nq2" ,
       M.call (|
-        M.get_name (| globals, "BNP12" |),
+        M.get_name (| globals, locals_stack, "BNP12" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "q1" |), "x" |), "frobenius" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "q1" |), "x" |), "frobenius" |),
             make_list [],
             make_dict []
           |);
           UnOp.sub (| M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "q1" |), "y" |), "frobenius" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "q1" |), "y" |), "frobenius" |),
             make_list [],
             make_dict []
           |) |)
@@ -705,13 +713,13 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "f" ,
       BinOp.mult (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         M.call (|
-          M.get_name (| globals, "linefunc" |),
+          M.get_name (| globals, locals_stack, "linefunc" |),
           make_list [
-            M.get_name (| globals, "r" |);
-            M.get_name (| globals, "q1" |);
-            M.get_name (| globals, "p" |)
+            M.get_name (| globals, locals_stack, "r" |);
+            M.get_name (| globals, locals_stack, "q1" |);
+            M.get_name (| globals, locals_stack, "p" |)
           ],
           make_dict []
         |)
@@ -720,20 +728,20 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       BinOp.add (|
-        M.get_name (| globals, "r" |),
-        M.get_name (| globals, "q1" |)
+        M.get_name (| globals, locals_stack, "r" |),
+        M.get_name (| globals, locals_stack, "q1" |)
       |)
     |) in
     let _ := M.assign_local (|
       "f" ,
       BinOp.mult (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         M.call (|
-          M.get_name (| globals, "linefunc" |),
+          M.get_name (| globals, locals_stack, "linefunc" |),
           make_list [
-            M.get_name (| globals, "r" |);
-            M.get_name (| globals, "nq2" |);
-            M.get_name (| globals, "p" |)
+            M.get_name (| globals, locals_stack, "r" |);
+            M.get_name (| globals, locals_stack, "nq2" |);
+            M.get_name (| globals, locals_stack, "p" |)
           ],
           make_dict []
         |)
@@ -741,42 +749,43 @@ Definition miller_loop : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         BinOp.floor_div (|
           BinOp.sub (|
             BinOp.pow (|
-              M.get_name (| globals, "ALT_BN128_PRIME" |),
+              M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |),
               Constant.int 12
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+          M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
         |)
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition pairing : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "q"; "p" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "q"; "p" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the pairing of `q` and `p`.
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "miller_loop" |),
+        M.get_name (| globals, locals_stack, "miller_loop" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "twist" |),
+            M.get_name (| globals, locals_stack, "twist" |),
             make_list [
-              M.get_name (| globals, "q" |)
+              M.get_name (| globals, locals_stack, "q" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "bnp_to_bnp12" |),
+            M.get_name (| globals, locals_stack, "bnp_to_bnp12" |),
             make_list [
-              M.get_name (| globals, "p" |)
+              M.get_name (| globals, locals_stack, "p" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/crypto/blake2.v b/CoqOfPython/ethereum/crypto/blake2.v
index 6cd27f7..6363258 100644
--- a/CoqOfPython/ethereum/crypto/blake2.v
+++ b/CoqOfPython/ethereum/crypto/blake2.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.blake2".
+Definition globals : Globals.t := "ethereum.crypto.blake2".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -22,8 +24,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition spit_le_to_uint : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data"; "start"; "num_words" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data"; "start"; "num_words" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts 8 byte words from a given data.
 
@@ -42,11 +45,11 @@ Definition spit_le_to_uint : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_words" |)
+        M.get_name (| globals, locals_stack, "num_words" |)
       ],
       make_dict []
     |),
@@ -54,24 +57,24 @@ Definition spit_le_to_uint : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "start_position" ,
             BinOp.add (|
-              M.get_name (| globals, "start" |),
+              M.get_name (| globals, locals_stack, "start" |),
               BinOp.mult (|
-                M.get_name (| globals, "i" |),
+                M.get_name (| globals, locals_stack, "i" |),
                 Constant.int 8
               |)
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "words" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "words" |), "append" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_le_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_le_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "data" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "data" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
-              M.get_name (| globals, "start_position" |),
+              M.get_name (| globals, locals_stack, "start_position" |),
               Constant.int 8
             |),
             Constant.None_
@@ -89,7 +92,7 @@ Definition spit_le_to_uint : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "words" |)
+      M.get_name (| globals, locals_stack, "words" |)
     |) in
     M.pure Constant.None_)).
 
@@ -102,8 +105,9 @@ Definition Blake2 : Value.t :=
     [
       (
         "get_blake2_parameters",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "data" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "data" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Extract the parameters required in the Blake2 compression function
         from the provided bytes data.
@@ -116,10 +120,10 @@ Definition Blake2 : Value.t :=
           let _ := M.assign_local (|
             "rounds" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
               make_list [
                 M.slice (|
-                  M.get_name (| globals, "data" |),
+                  M.get_name (| globals, locals_stack, "data" |),
                   Constant.None_,
                   Constant.int 4,
                   Constant.None_
@@ -131,9 +135,9 @@ Definition Blake2 : Value.t :=
           let _ := M.assign_local (|
             "h" ,
             M.call (|
-              M.get_name (| globals, "spit_le_to_uint" |),
+              M.get_name (| globals, locals_stack, "spit_le_to_uint" |),
               make_list [
-                M.get_name (| globals, "data" |);
+                M.get_name (| globals, locals_stack, "data" |);
                 Constant.int 4;
                 Constant.int 8
               ],
@@ -143,9 +147,9 @@ Definition Blake2 : Value.t :=
           let _ := M.assign_local (|
             "m" ,
             M.call (|
-              M.get_name (| globals, "spit_le_to_uint" |),
+              M.get_name (| globals, locals_stack, "spit_le_to_uint" |),
               make_list [
-                M.get_name (| globals, "data" |);
+                M.get_name (| globals, locals_stack, "data" |);
                 Constant.int 68;
                 Constant.int 16
               ],
@@ -153,11 +157,11 @@ Definition Blake2 : Value.t :=
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |) ],
             M.call (|
-              M.get_name (| globals, "spit_le_to_uint" |),
+              M.get_name (| globals, locals_stack, "spit_le_to_uint" |),
               make_list [
-                M.get_name (| globals, "data" |);
+                M.get_name (| globals, locals_stack, "data" |);
                 Constant.int 196;
                 Constant.int 2
               ],
@@ -167,10 +171,10 @@ Definition Blake2 : Value.t :=
           let _ := M.assign_local (|
             "f" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
               make_list [
                 M.slice (|
-                  M.get_name (| globals, "data" |),
+                  M.get_name (| globals, locals_stack, "data" |),
                   Constant.int 212,
                   Constant.None_,
                   Constant.None_
@@ -180,14 +184,15 @@ Definition Blake2 : Value.t :=
             |)
           |) in
           let _ := M.return_ (|
-            make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ]
           |) in
           M.pure Constant.None_))
       );
       (
         "G",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "v"; "a"; "b"; "c"; "d"; "x"; "y" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "v"; "a"; "b"; "c"; "d"; "x"; "y" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         The mixing function used in Blake2
         https://datatracker.ietf.org/doc/html/rfc7693#section-3.1
@@ -203,243 +208,244 @@ Definition Blake2 : Value.t :=
         " in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "a" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "a" |)
             |),
             BinOp.mod_ (|
               BinOp.add (|
                 BinOp.add (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "a" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "a" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "b" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "b" |)
                   |)
                 |),
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               |),
-              M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "d" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "d" |)
             |),
             BinOp.bit_xor (|
               BinOp.r_shift (|
                 BinOp.bit_xor (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "d" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "d" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "a" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "a" |)
                   |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "R1" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "R1" |)
               |),
               BinOp.mod_ (|
                 BinOp.l_shift (|
                   BinOp.bit_xor (|
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "d" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "d" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "a" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "a" |)
                     |)
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "w_R1" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "w_R1" |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
               |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "c" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "c" |)
             |),
             BinOp.mod_ (|
               BinOp.add (|
                 M.get_subscript (|
-                  M.get_name (| globals, "v" |),
-                  M.get_name (| globals, "c" |)
+                  M.get_name (| globals, locals_stack, "v" |),
+                  M.get_name (| globals, locals_stack, "c" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "v" |),
-                  M.get_name (| globals, "d" |)
+                  M.get_name (| globals, locals_stack, "v" |),
+                  M.get_name (| globals, locals_stack, "d" |)
                 |)
               |),
-              M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "b" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "b" |)
             |),
             BinOp.bit_xor (|
               BinOp.r_shift (|
                 BinOp.bit_xor (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "b" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "b" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "c" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "c" |)
                   |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "R2" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "R2" |)
               |),
               BinOp.mod_ (|
                 BinOp.l_shift (|
                   BinOp.bit_xor (|
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "b" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "c" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "c" |)
                     |)
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "w_R2" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "w_R2" |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
               |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "a" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "a" |)
             |),
             BinOp.mod_ (|
               BinOp.add (|
                 BinOp.add (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "a" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "a" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "b" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "b" |)
                   |)
                 |),
-                M.get_name (| globals, "y" |)
+                M.get_name (| globals, locals_stack, "y" |)
               |),
-              M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "d" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "d" |)
             |),
             BinOp.bit_xor (|
               BinOp.r_shift (|
                 BinOp.bit_xor (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "d" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "d" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "a" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "a" |)
                   |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "R3" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "R3" |)
               |),
               BinOp.mod_ (|
                 BinOp.l_shift (|
                   BinOp.bit_xor (|
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "d" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "d" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "a" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "a" |)
                     |)
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "w_R3" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "w_R3" |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
               |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "c" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "c" |)
             |),
             BinOp.mod_ (|
               BinOp.add (|
                 M.get_subscript (|
-                  M.get_name (| globals, "v" |),
-                  M.get_name (| globals, "c" |)
+                  M.get_name (| globals, locals_stack, "v" |),
+                  M.get_name (| globals, locals_stack, "c" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "v" |),
-                  M.get_name (| globals, "d" |)
+                  M.get_name (| globals, locals_stack, "v" |),
+                  M.get_name (| globals, locals_stack, "d" |)
                 |)
               |),
-              M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
-              M.get_name (| globals, "b" |)
+              M.get_name (| globals, locals_stack, "v" |),
+              M.get_name (| globals, locals_stack, "b" |)
             |),
             BinOp.bit_xor (|
               BinOp.r_shift (|
                 BinOp.bit_xor (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "b" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "b" |)
                   |),
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
-                    M.get_name (| globals, "c" |)
+                    M.get_name (| globals, locals_stack, "v" |),
+                    M.get_name (| globals, locals_stack, "c" |)
                   |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "R4" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "R4" |)
               |),
               BinOp.mod_ (|
                 BinOp.l_shift (|
                   BinOp.bit_xor (|
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "b" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "v" |),
-                      M.get_name (| globals, "c" |)
+                      M.get_name (| globals, locals_stack, "v" |),
+                      M.get_name (| globals, locals_stack, "c" |)
                     |)
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "w_R4" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "w_R4" |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "max_word" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "max_word" |)
               |)
             |)
           |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "v" |)
+            M.get_name (| globals, locals_stack, "v" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "compress",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "num_rounds"; "h"; "m"; "t_0"; "t_1"; "f" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "num_rounds"; "h"; "m"; "t_0"; "t_1"; "f" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         'F Compression' from section 3.2 of RFC 7693:
         https://tools.ietf.org/html/rfc7693#section-3.2
@@ -468,44 +474,44 @@ Definition Blake2 : Value.t :=
           |) in
           let _ := M.assign (|
             M.slice (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 0,
               Constant.int 8,
               Constant.None_
             |),
-            M.get_name (| globals, "h" |)
+            M.get_name (| globals, locals_stack, "h" |)
           |) in
           let _ := M.assign (|
             M.slice (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 8,
               Constant.int 15,
               Constant.None_
             |),
-            M.get_field (| M.get_name (| globals, "self" |), "IV" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "IV" |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 12
             |),
             BinOp.bit_xor (|
-              M.get_name (| globals, "t_0" |),
+              M.get_name (| globals, locals_stack, "t_0" |),
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "self" |), "IV" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "IV" |),
                 Constant.int 4
               |)
             |)
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 13
             |),
             BinOp.bit_xor (|
-              M.get_name (| globals, "t_1" |),
+              M.get_name (| globals, locals_stack, "t_1" |),
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "self" |), "IV" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "IV" |),
                 Constant.int 5
               |)
             |)
@@ -513,20 +519,20 @@ Definition Blake2 : Value.t :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_name (| globals, "f" |),
+              M.get_name (| globals, locals_stack, "f" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign (|
                 M.get_subscript (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 14
                 |),
                 BinOp.bit_xor (|
                   M.get_subscript (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 14
                   |),
-                  M.get_field (| M.get_name (| globals, "self" |), "mask_bits" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "mask_bits" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -536,11 +542,11 @@ Definition Blake2 : Value.t :=
             )) |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "r" |),
+              M.get_name (| globals, locals_stack, "r" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_rounds" |)
+        M.get_name (| globals, locals_stack, "num_rounds" |)
       ],
       make_dict []
     |),
@@ -548,34 +554,34 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "s" ,
                   M.get_subscript (|
-                    M.get_field (| M.get_name (| globals, "self" |), "sigma" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "sigma" |),
                     BinOp.mod_ (|
-                      M.get_name (| globals, "r" |),
-                      M.get_field (| M.get_name (| globals, "self" |), "sigma_len" |)
+                      M.get_name (| globals, locals_stack, "r" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "sigma_len" |)
                     |)
                   |)
                 |) in
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 0;
                       Constant.int 4;
                       Constant.int 8;
                       Constant.int 12;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 0
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 1
                         |)
                       |)
@@ -586,24 +592,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 1;
                       Constant.int 5;
                       Constant.int 9;
                       Constant.int 13;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 2
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 3
                         |)
                       |)
@@ -614,24 +620,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 2;
                       Constant.int 6;
                       Constant.int 10;
                       Constant.int 14;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 4
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 5
                         |)
                       |)
@@ -642,24 +648,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 3;
                       Constant.int 7;
                       Constant.int 11;
                       Constant.int 15;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 6
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 7
                         |)
                       |)
@@ -670,24 +676,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 0;
                       Constant.int 5;
                       Constant.int 10;
                       Constant.int 15;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 8
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 9
                         |)
                       |)
@@ -698,24 +704,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 1;
                       Constant.int 6;
                       Constant.int 11;
                       Constant.int 12;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 10
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 11
                         |)
                       |)
@@ -726,24 +732,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 2;
                       Constant.int 7;
                       Constant.int 8;
                       Constant.int 13;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 12
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 13
                         |)
                       |)
@@ -754,24 +760,24 @@ Definition Blake2 : Value.t :=
                 let _ := M.assign_local (|
                   "v" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "self" |), "G" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "G" |),
                     make_list [
-                      M.get_name (| globals, "v" |);
+                      M.get_name (| globals, locals_stack, "v" |);
                       Constant.int 3;
                       Constant.int 4;
                       Constant.int 9;
                       Constant.int 14;
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 14
                         |)
                       |);
                       M.get_subscript (|
-                        M.get_name (| globals, "m" |),
+                        M.get_name (| globals, locals_stack, "m" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "s" |),
+                          M.get_name (| globals, locals_stack, "s" |),
                           Constant.int 15
                         |)
                       |)
@@ -791,15 +797,15 @@ Definition Blake2 : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "struct" |), "pack" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "struct" |), "pack" |),
               make_list_concat (| [
                 make_list [
                   BinOp.mod_ (|
                     Constant.str "<8%s",
-                    M.get_field (| M.get_name (| globals, "self" |), "word_format" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "word_format" |)
                   |)
                 ];
-                M.get_name (| globals, "result_message_words" |)
+                M.get_name (| globals, locals_stack, "result_message_words" |)
               ] |),
               make_dict []
             |)
diff --git a/CoqOfPython/ethereum/crypto/elliptic_curve.v b/CoqOfPython/ethereum/crypto/elliptic_curve.v
index 3b7436b..c8adbad 100644
--- a/CoqOfPython/ethereum/crypto/elliptic_curve.v
+++ b/CoqOfPython/ethereum/crypto/elliptic_curve.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.elliptic_curve".
+Definition globals : Globals.t := "ethereum.crypto.elliptic_curve".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,7 +36,7 @@ Definition SECP256K1N : Value.t := M.run ltac:(M.monadic (
 
 Definition F : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "F"
     ],
@@ -44,7 +46,7 @@ Definition F : Value.t := M.run ltac:(M.monadic (
 
 Definition T : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "T"
     ],
@@ -53,8 +55,9 @@ Definition T : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition secp256k1_recover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "r"; "s"; "v"; "msg_hash" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "r"; "s"; "v"; "msg_hash" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Recovers the public key from a given signature.
 
@@ -77,7 +80,7 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r_bytes" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "r" |), "to_be_bytes32" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "r" |), "to_be_bytes32" |),
         make_list [],
         make_dict []
       |)
@@ -85,7 +88,7 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s_bytes" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "s" |), "to_be_bytes32" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "s" |), "to_be_bytes32" |),
         make_list [],
         make_dict []
       |)
@@ -93,7 +96,7 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "signature" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             make_list [
@@ -107,13 +110,13 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "signature" |),
+        M.get_name (| globals, locals_stack, "signature" |),
         BinOp.sub (|
           Constant.int 32,
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "r_bytes" |)
+              M.get_name (| globals, locals_stack, "r_bytes" |)
             ],
             make_dict []
           |)
@@ -121,17 +124,17 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
         Constant.int 32,
         Constant.None_
       |),
-      M.get_name (| globals, "r_bytes" |)
+      M.get_name (| globals, locals_stack, "r_bytes" |)
     |) in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "signature" |),
+        M.get_name (| globals, locals_stack, "signature" |),
         BinOp.sub (|
           Constant.int 64,
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "s_bytes" |)
+              M.get_name (| globals, locals_stack, "s_bytes" |)
             ],
             make_dict []
           |)
@@ -139,28 +142,28 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
         Constant.int 64,
         Constant.None_
       |),
-      M.get_name (| globals, "s_bytes" |)
+      M.get_name (| globals, locals_stack, "s_bytes" |)
     |) in
     let _ := M.assign (|
       M.get_subscript (|
-        M.get_name (| globals, "signature" |),
+        M.get_name (| globals, locals_stack, "signature" |),
         Constant.int 64
       |),
-      M.get_name (| globals, "v" |)
+      M.get_name (| globals, locals_stack, "v" |)
     |) in
     let _ := M.assign_local (|
       "public_key" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "coincurve" |), "PublicKey" |), "from_signature_and_message" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "coincurve" |), "PublicKey" |), "from_signature_and_message" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
-              M.get_name (| globals, "signature" |)
+              M.get_name (| globals, locals_stack, "signature" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "msg_hash" |)
+          M.get_name (| globals, locals_stack, "msg_hash" |)
         ],
         make_dict []
       |)
@@ -169,7 +172,7 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
       "public_key" ,
       M.slice (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "public_key" |), "format" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "public_key" |), "format" |),
           make_list [],
           make_dict []
         |),
@@ -179,7 +182,7 @@ Definition secp256k1_recover : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "public_key" |)
+      M.get_name (| globals, locals_stack, "public_key" |)
     |) in
     M.pure Constant.None_)).
 
@@ -189,8 +192,9 @@ Definition EllipticCurve : Value.t :=
     [
       (
         "point_at_infinity",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Return the point at infinity. This is the identity element of the group
         operation.
@@ -200,16 +204,16 @@ Definition EllipticCurve : Value.t :=
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "cls" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 M.call (|
-                  M.get_field (| M.get_field (| M.get_name (| globals, "cls" |), "FIELD" |), "zero" |),
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "FIELD" |), "zero" |),
                   make_list [],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_field (| M.get_name (| globals, "cls" |), "FIELD" |), "zero" |),
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "FIELD" |), "zero" |),
                   make_list [],
                   make_dict []
                 |)
@@ -223,8 +227,9 @@ Definition EllipticCurve : Value.t :=
     [
       (
         "__new__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "x"; "y" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "x"; "y" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Make new point on the curve. The point is not checked to see if it is
         on the curve.
@@ -232,30 +237,31 @@ Definition EllipticCurve : Value.t :=
           let _ := M.assign_local (|
             "res" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "object" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "object" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |)
+                M.get_name (| globals, locals_stack, "cls" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "res" |), "x" |),
-            M.get_name (| globals, "x" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "res" |), "x" |),
+            M.get_name (| globals, locals_stack, "x" |)
           |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "res" |), "y" |),
-            M.get_name (| globals, "y" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "res" |), "y" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "res" |)
+            M.get_name (| globals, locals_stack, "res" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "x"; "y" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "x"; "y" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Checks if the point is on the curve. To skip this check call
         `__new__()` directly.
@@ -266,18 +272,18 @@ Definition EllipticCurve : Value.t :=
               BoolOp.and (|
                 BoolOp.or (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "x" |),
+                    M.get_name (| globals, locals_stack, "x" |),
                     M.call (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
                       make_list [],
                       make_dict []
                     |)
                   |),
                   ltac:(M.monadic (
                     Compare.not_eq (|
-                      M.get_name (| globals, "y" |),
+                      M.get_name (| globals, locals_stack, "y" |),
                       M.call (|
-                        M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
                         make_list [],
                         make_dict []
                       |)
@@ -290,23 +296,23 @@ Definition EllipticCurve : Value.t :=
                       BinOp.sub (|
                         BinOp.sub (|
                           BinOp.pow (|
-                            M.get_name (| globals, "y" |),
+                            M.get_name (| globals, locals_stack, "y" |),
                             Constant.int 2
                           |),
                           BinOp.pow (|
-                            M.get_name (| globals, "x" |),
+                            M.get_name (| globals, locals_stack, "x" |),
                             Constant.int 3
                           |)
                         |),
                         BinOp.mult (|
-                          M.get_field (| M.get_name (| globals, "self" |), "A" |),
-                          M.get_name (| globals, "x" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "self" |), "A" |),
+                          M.get_name (| globals, locals_stack, "x" |)
                         |)
                       |),
-                      M.get_field (| M.get_name (| globals, "self" |), "B" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "B" |)
                     |),
                     M.call (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
                       make_list [],
                       make_dict []
                     |)
@@ -316,7 +322,7 @@ Definition EllipticCurve : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.raise (| Some (M.call (|
-                M.get_name (| globals, "ValueError" |),
+                M.get_name (| globals, locals_stack, "ValueError" |),
                 make_list [
                   Constant.str "Point not on curve"
                 ],
@@ -331,8 +337,9 @@ Definition EllipticCurve : Value.t :=
       );
       (
         "__eq__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "other" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "other" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Test two points for equality.
         " in
@@ -340,13 +347,13 @@ Definition EllipticCurve : Value.t :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "other" |);
+                  M.get_name (| globals, locals_stack, "other" |);
                   M.call (|
-                    M.get_name (| globals, "type" |),
+                    M.get_name (| globals, locals_stack, "type" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |)
@@ -366,13 +373,13 @@ Definition EllipticCurve : Value.t :=
           let _ := M.return_ (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "self" |), "x" |),
-                M.get_field (| M.get_name (| globals, "other" |), "x" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "x" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "other" |), "x" |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "self" |), "y" |),
-                  M.get_field (| M.get_name (| globals, "other" |), "y" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "y" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "other" |), "y" |)
                 |)
               ))
             |)
@@ -381,16 +388,17 @@ Definition EllipticCurve : Value.t :=
       );
       (
         "__str__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Stringify a point as its coordinates.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "str" |),
+              M.get_name (| globals, locals_stack, "str" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "self" |), "x" |); M.get_field (| M.get_name (| globals, "self" |), "y" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "self" |), "x" |); M.get_field (| M.get_name (| globals, locals_stack, "self" |), "y" |) ]
               ],
               make_dict []
             |)
@@ -399,26 +407,27 @@ Definition EllipticCurve : Value.t :=
       );
       (
         "double",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Add a point to itself.
         " in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "x" |); M.get_name (| globals, "y" |); M.get_name (| globals, "F" |) ],
-            make_tuple [ M.get_field (| M.get_name (| globals, "self" |), "x" |); M.get_field (| M.get_name (| globals, "self" |), "y" |); M.get_field (| M.get_name (| globals, "self" |), "FIELD" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "x" |); M.get_name (| globals, locals_stack, "y" |); M.get_name (| globals, locals_stack, "F" |) ],
+            make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "self" |), "x" |); M.get_field (| M.get_name (| globals, locals_stack, "self" |), "y" |); M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |) ]
           |) in
           let _ :=
             (* if *)
             M.if_then_else (|
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_name (| globals, "x" |),
+                  M.get_name (| globals, locals_stack, "x" |),
                   Constant.int 0
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_name (| globals, "y" |),
+                    M.get_name (| globals, locals_stack, "y" |),
                     Constant.int 0
                   |)
                 ))
@@ -426,7 +435,7 @@ Definition EllipticCurve : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "self" |)
+                M.get_name (| globals, locals_stack, "self" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -439,28 +448,28 @@ Definition EllipticCurve : Value.t :=
               BinOp.add (|
                 BinOp.mult (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "F" |), "from_int" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "F" |), "from_int" |),
                     make_list [
                       Constant.int 3
                     ],
                     make_dict []
                   |),
                   BinOp.pow (|
-                    M.get_name (| globals, "x" |),
+                    M.get_name (| globals, locals_stack, "x" |),
                     Constant.int 2
                   |)
                 |),
-                M.get_field (| M.get_name (| globals, "self" |), "A" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "A" |)
               |),
               BinOp.mult (|
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "F" |), "from_int" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "F" |), "from_int" |),
                   make_list [
                     Constant.int 2
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "y" |)
+                M.get_name (| globals, locals_stack, "y" |)
               |)
             |)
           |) in
@@ -469,40 +478,40 @@ Definition EllipticCurve : Value.t :=
             BinOp.sub (|
               BinOp.sub (|
                 BinOp.pow (|
-                  M.get_name (| globals, "lam" |),
+                  M.get_name (| globals, locals_stack, "lam" |),
                   Constant.int 2
                 |),
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               |),
-              M.get_name (| globals, "x" |)
+              M.get_name (| globals, locals_stack, "x" |)
             |)
           |) in
           let _ := M.assign_local (|
             "new_y" ,
             BinOp.sub (|
               BinOp.mult (|
-                M.get_name (| globals, "lam" |),
+                M.get_name (| globals, locals_stack, "lam" |),
                 BinOp.sub (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "new_x" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "new_x" |)
                 |)
               |),
-              M.get_name (| globals, "y" |)
+              M.get_name (| globals, locals_stack, "y" |)
             |)
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
-                M.get_name (| globals, "new_x" |);
-                M.get_name (| globals, "new_y" |)
+                M.get_name (| globals, locals_stack, "new_x" |);
+                M.get_name (| globals, locals_stack, "new_y" |)
               ],
               make_dict []
             |)
@@ -511,42 +520,43 @@ Definition EllipticCurve : Value.t :=
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "other" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "other" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Add two points together.
         " in
           let _ := M.assign_local (|
             "ZERO" ,
             M.call (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "self_x" |); M.get_name (| globals, "self_y" |); M.get_name (| globals, "other_x" |); M.get_name (| globals, "other_y" |) ],
-            make_tuple [ M.get_field (| M.get_name (| globals, "self" |), "x" |); M.get_field (| M.get_name (| globals, "self" |), "y" |); M.get_field (| M.get_name (| globals, "other" |), "x" |); M.get_field (| M.get_name (| globals, "other" |), "y" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "self_x" |); M.get_name (| globals, locals_stack, "self_y" |); M.get_name (| globals, locals_stack, "other_x" |); M.get_name (| globals, locals_stack, "other_y" |) ],
+            make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "self" |), "x" |); M.get_field (| M.get_name (| globals, locals_stack, "self" |), "y" |); M.get_field (| M.get_name (| globals, locals_stack, "other" |), "x" |); M.get_field (| M.get_name (| globals, locals_stack, "other" |), "y" |) ]
           |) in
           let _ :=
             (* if *)
             M.if_then_else (|
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_name (| globals, "self_x" |),
-                  M.get_name (| globals, "ZERO" |)
+                  M.get_name (| globals, locals_stack, "self_x" |),
+                  M.get_name (| globals, locals_stack, "ZERO" |)
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_name (| globals, "self_y" |),
-                    M.get_name (| globals, "ZERO" |)
+                    M.get_name (| globals, locals_stack, "self_y" |),
+                    M.get_name (| globals, locals_stack, "ZERO" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "other" |)
+                M.get_name (| globals, locals_stack, "other" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -558,20 +568,20 @@ Definition EllipticCurve : Value.t :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_name (| globals, "other_x" |),
-                  M.get_name (| globals, "ZERO" |)
+                  M.get_name (| globals, locals_stack, "other_x" |),
+                  M.get_name (| globals, locals_stack, "ZERO" |)
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_name (| globals, "other_y" |),
-                    M.get_name (| globals, "ZERO" |)
+                    M.get_name (| globals, locals_stack, "other_y" |),
+                    M.get_name (| globals, locals_stack, "ZERO" |)
                   |)
                 ))
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "self" |)
+                M.get_name (| globals, locals_stack, "self" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -582,8 +592,8 @@ Definition EllipticCurve : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "self_x" |),
-                M.get_name (| globals, "other_x" |)
+                M.get_name (| globals, locals_stack, "self_x" |),
+                M.get_name (| globals, locals_stack, "other_x" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -591,14 +601,14 @@ Definition EllipticCurve : Value.t :=
                 (* if *)
                 M.if_then_else (|
                   Compare.eq (|
-                    M.get_name (| globals, "self_y" |),
-                    M.get_name (| globals, "other_y" |)
+                    M.get_name (| globals, locals_stack, "self_y" |),
+                    M.get_name (| globals, locals_stack, "other_y" |)
                   |),
                 (* then *)
                 ltac:(M.monadic (
                   let _ := M.return_ (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "self" |), "double" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "double" |),
                       make_list [],
                       make_dict []
                     |)
@@ -608,7 +618,7 @@ Definition EllipticCurve : Value.t :=
                 )), ltac:(M.monadic (
                   let _ := M.return_ (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "self" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "self" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -624,12 +634,12 @@ Definition EllipticCurve : Value.t :=
             "lam" ,
             BinOp.div (|
               BinOp.sub (|
-                M.get_name (| globals, "other_y" |),
-                M.get_name (| globals, "self_y" |)
+                M.get_name (| globals, locals_stack, "other_y" |),
+                M.get_name (| globals, locals_stack, "self_y" |)
               |),
               BinOp.sub (|
-                M.get_name (| globals, "other_x" |),
-                M.get_name (| globals, "self_x" |)
+                M.get_name (| globals, locals_stack, "other_x" |),
+                M.get_name (| globals, locals_stack, "self_x" |)
               |)
             |)
           |) in
@@ -638,40 +648,40 @@ Definition EllipticCurve : Value.t :=
             BinOp.sub (|
               BinOp.sub (|
                 BinOp.pow (|
-                  M.get_name (| globals, "lam" |),
+                  M.get_name (| globals, locals_stack, "lam" |),
                   Constant.int 2
                 |),
-                M.get_name (| globals, "self_x" |)
+                M.get_name (| globals, locals_stack, "self_x" |)
               |),
-              M.get_name (| globals, "other_x" |)
+              M.get_name (| globals, locals_stack, "other_x" |)
             |)
           |) in
           let _ := M.assign_local (|
             "y" ,
             BinOp.sub (|
               BinOp.mult (|
-                M.get_name (| globals, "lam" |),
+                M.get_name (| globals, locals_stack, "lam" |),
                 BinOp.sub (|
-                  M.get_name (| globals, "self_x" |),
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "self_x" |),
+                  M.get_name (| globals, locals_stack, "x" |)
                 |)
               |),
-              M.get_name (| globals, "self_y" |)
+              M.get_name (| globals, locals_stack, "self_y" |)
             |)
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
-                M.get_name (| globals, "x" |);
-                M.get_name (| globals, "y" |)
+                M.get_name (| globals, locals_stack, "x" |);
+                M.get_name (| globals, locals_stack, "y" |)
               ],
               make_dict []
             |)
@@ -680,30 +690,31 @@ Definition EllipticCurve : Value.t :=
       );
       (
         "mul_by",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "n" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "n" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Multiply `self` by `n` using the double and add algorithm.
         " in
           let _ := M.assign_local (|
             "res" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
                   make_list [],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_field (| M.get_name (| globals, "self" |), "FIELD" |), "zero" |),
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FIELD" |), "zero" |),
                   make_list [],
                   make_dict []
                 |)
@@ -713,12 +724,12 @@ Definition EllipticCurve : Value.t :=
           |) in
           let _ := M.assign_local (|
             "s" ,
-            M.get_name (| globals, "self" |)
+            M.get_name (| globals, locals_stack, "self" |)
           |) in
           let _ :=
             M.while (|
               Compare.not_eq (|
-      M.get_name (| globals, "n" |),
+      M.get_name (| globals, locals_stack, "n" |),
       Constant.int 0
     |),
               ltac:(M.monadic (
@@ -727,7 +738,7 @@ Definition EllipticCurve : Value.t :=
                   M.if_then_else (|
                     Compare.eq (|
                       BinOp.mod_ (|
-                        M.get_name (| globals, "n" |),
+                        M.get_name (| globals, locals_stack, "n" |),
                         Constant.int 2
                       |),
                       Constant.int 1
@@ -737,8 +748,8 @@ Definition EllipticCurve : Value.t :=
                     let _ := M.assign_local (|
                       "res" ,
                       BinOp.add (|
-                        M.get_name (| globals, "res" |),
-                        M.get_name (| globals, "s" |)
+                        M.get_name (| globals, locals_stack, "res" |),
+                        M.get_name (| globals, locals_stack, "s" |)
                       |)
                     |) in
                     M.pure Constant.None_
@@ -749,8 +760,8 @@ Definition EllipticCurve : Value.t :=
                 let _ := M.assign_local (|
                   "s" ,
                   BinOp.add (|
-                    M.get_name (| globals, "s" |),
-                    M.get_name (| globals, "s" |)
+                    M.get_name (| globals, locals_stack, "s" |),
+                    M.get_name (| globals, locals_stack, "s" |)
                   |)
                 |) in
                 let _ := M.assign_op_local (|
@@ -765,7 +776,7 @@ Definition EllipticCurve : Value.t :=
               ))
           |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "res" |)
+            M.get_name (| globals, locals_stack, "res" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/crypto/finite_field.v b/CoqOfPython/ethereum/crypto/finite_field.v
index fa90840..458e285 100644
--- a/CoqOfPython/ethereum/crypto/finite_field.v
+++ b/CoqOfPython/ethereum/crypto/finite_field.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.finite_field".
+Definition globals : Globals.t := "ethereum.crypto.finite_field".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -31,7 +33,7 @@ Axiom ethereum_base_types_imports_Bytes32 :
 
 Definition F : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "F"
     ],
@@ -45,15 +47,17 @@ Definition Field : Value.t :=
     [
       (
         "zero",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "from_int",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "n" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "n" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       )
@@ -61,85 +65,97 @@ Definition Field : Value.t :=
     [
       (
         "__radd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__iadd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__sub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__rsub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__rmul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__imul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__pow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "exponent" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "exponent" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__ipow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__neg__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       );
       (
         "__truediv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := Constant.ellipsis in
           M.pure Constant.None_))
       )
@@ -147,7 +163,7 @@ Definition Field : Value.t :=
 
 Definition T : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "T"
     ],
@@ -161,8 +177,9 @@ Definition PrimeField : Value.t :=
     [
       (
         "from_be_bytes",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "buffer" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "buffer" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts a sequence of bytes into a element of the field.
         Parameters
@@ -176,12 +193,12 @@ Definition PrimeField : Value.t :=
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "from_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "from_bytes" |),
                   make_list [
-                    M.get_name (| globals, "buffer" |);
+                    M.get_name (| globals, locals_stack, "buffer" |);
                     Constant.str "big"
                   ],
                   make_dict []
@@ -194,13 +211,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "zero",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "cls" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 Constant.int 0
               ],
               make_dict []
@@ -210,13 +228,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "from_int",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "n" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "n" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               make_list [
-                M.get_name (| globals, "n" |)
+                M.get_name (| globals, locals_stack, "n" |)
               ],
               make_dict []
             |)
@@ -227,16 +246,17 @@ Definition PrimeField : Value.t :=
     [
       (
         "__new__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "value" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "value" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "int" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 BinOp.mod_ (|
-                  M.get_name (| globals, "value" |),
-                  M.get_field (| M.get_name (| globals, "cls" |), "PRIME" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "PRIME" |)
                 |)
               ],
               make_dict []
@@ -246,13 +266,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__radd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -261,23 +282,24 @@ Definition PrimeField : Value.t :=
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -286,20 +308,20 @@ Definition PrimeField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__add__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__add__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -311,13 +333,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__iadd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -326,23 +349,24 @@ Definition PrimeField : Value.t :=
       );
       (
         "__sub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -351,20 +375,20 @@ Definition PrimeField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__sub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__sub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -376,23 +400,24 @@ Definition PrimeField : Value.t :=
       );
       (
         "__rsub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "left" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -401,20 +426,20 @@ Definition PrimeField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__rsub__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__rsub__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "left" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "left" |)
                   ],
                   make_dict []
                 |)
@@ -426,23 +451,24 @@ Definition PrimeField : Value.t :=
       );
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
-                  M.get_name (| globals, "int" |)
+                  M.get_name (| globals, locals_stack, "right" |);
+                  M.get_name (| globals, locals_stack, "int" |)
                 ],
                 make_dict []
               |) |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -451,20 +477,20 @@ Definition PrimeField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__mul__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__mul__" |),
                   make_list [
-                    M.get_name (| globals, "self" |);
-                    M.get_name (| globals, "right" |)
+                    M.get_name (| globals, locals_stack, "self" |);
+                    M.get_name (| globals, locals_stack, "right" |)
                   ],
                   make_dict []
                 |)
@@ -476,13 +502,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__rmul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -491,13 +518,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__imul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -506,31 +534,32 @@ Definition PrimeField : Value.t :=
       );
       (
         "__pow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "exponent" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "exponent" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__pow__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__pow__" |),
                   make_list [
                     M.call (|
-                      M.get_name (| globals, "int" |),
+                      M.get_name (| globals, locals_stack, "int" |),
                       make_list [
-                        M.get_name (| globals, "self" |)
+                        M.get_name (| globals, locals_stack, "self" |)
                       ],
                       make_dict []
                     |);
-                    M.get_name (| globals, "exponent" |);
-                    M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+                    M.get_name (| globals, locals_stack, "exponent" |);
+                    M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
                   ],
                   make_dict []
                 |)
@@ -542,13 +571,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__ipow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__pow__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__pow__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -557,23 +587,24 @@ Definition PrimeField : Value.t :=
       );
       (
         "__neg__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "int" |), "__neg__" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "int" |), "__neg__" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |)
@@ -585,13 +616,14 @@ Definition PrimeField : Value.t :=
       );
       (
         "__truediv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             BinOp.mult (|
-              M.get_name (| globals, "self" |),
+              M.get_name (| globals, locals_stack, "self" |),
               M.call (|
-                M.get_field (| M.get_name (| globals, "right" |), "multiplicative_inverse" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "right" |), "multiplicative_inverse" |),
                 make_list [],
                 make_dict []
               |)
@@ -601,11 +633,12 @@ Definition PrimeField : Value.t :=
       );
       (
         "multiplicative_inverse",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             BinOp.pow (|
-              M.get_name (| globals, "self" |),
+              M.get_name (| globals, locals_stack, "self" |),
               UnOp.sub (| Constant.int 1 |)
             |)
           |) in
@@ -613,8 +646,9 @@ Definition PrimeField : Value.t :=
       );
       (
         "to_be_bytes32",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Converts this arbitrarily sized unsigned integer into its big endian
         representation with exactly 32 bytes.
@@ -625,10 +659,10 @@ Definition PrimeField : Value.t :=
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "Bytes32" |),
+              M.get_name (| globals, locals_stack, "Bytes32" |),
               make_list [
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "to_bytes" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "to_bytes" |),
                   make_list [
                     Constant.int 32;
                     Constant.str "big"
@@ -645,7 +679,7 @@ Definition PrimeField : Value.t :=
 
 Definition U : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "U"
     ],
@@ -659,21 +693,22 @@ Definition GaloisField : Value.t :=
     [
       (
         "zero",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "cls" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 BinOp.mult (|
                   make_list [
                     Constant.int 0
                   ],
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "cls" |), "MODULUS" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MODULUS" |)
                     ],
                     make_dict []
                   |)
@@ -686,16 +721,17 @@ Definition GaloisField : Value.t :=
       );
       (
         "from_int",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "n" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "n" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "cls" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 BinOp.add (|
                   make_list [
-                    M.get_name (| globals, "n" |)
+                    M.get_name (| globals, locals_stack, "n" |)
                   ],
                   BinOp.mult (|
                     make_list [
@@ -703,9 +739,9 @@ Definition GaloisField : Value.t :=
                     ],
                     BinOp.sub (|
                       M.call (|
-                        M.get_name (| globals, "len" |),
+                        M.get_name (| globals, locals_stack, "len" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "cls" |), "MODULUS" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MODULUS" |)
                         ],
                         make_dict []
                       |),
@@ -721,8 +757,9 @@ Definition GaloisField : Value.t :=
       );
       (
         "calculate_frobenius_coefficients",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Calculate the coefficients needed by `frobenius()`.
         " in
@@ -732,14 +769,14 @@ Definition GaloisField : Value.t :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "cls" |), "MODULUS" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MODULUS" |)
           ],
           make_dict []
         |)
@@ -754,9 +791,9 @@ Definition GaloisField : Value.t :=
                       Constant.int 0
                     ],
                     M.call (|
-                      M.get_name (| globals, "len" |),
+                      M.get_name (| globals, locals_stack, "len" |),
                       make_list [
-                        M.get_field (| M.get_name (| globals, "cls" |), "MODULUS" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MODULUS" |)
                       ],
                       make_dict []
                     |)
@@ -764,24 +801,24 @@ Definition GaloisField : Value.t :=
                 |) in
                 let _ := M.assign (|
                   M.get_subscript (|
-                    M.get_name (| globals, "x" |),
-                    M.get_name (| globals, "i" |)
+                    M.get_name (| globals, locals_stack, "x" |),
+                    M.get_name (| globals, locals_stack, "i" |)
                   |),
                   Constant.int 1
                 |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "coefficients" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "coefficients" |), "append" |),
     make_list [
       BinOp.pow (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "cls" |), "__new__" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__new__" |),
           make_list [
-            M.get_name (| globals, "cls" |);
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "cls" |);
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "cls" |), "PRIME" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "PRIME" |)
       |)
     ],
     make_dict []
@@ -794,9 +831,9 @@ Definition GaloisField : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "tuple" |),
+              M.get_name (| globals, locals_stack, "tuple" |),
               make_list [
-                M.get_name (| globals, "coefficients" |)
+                M.get_name (| globals, locals_stack, "coefficients" |)
               ],
               make_dict []
             |)
@@ -807,14 +844,15 @@ Definition GaloisField : Value.t :=
     [
       (
         "__new__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "cls"; "iterable" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "iterable" ] in
+          ltac:(M.monadic (
           let _ := M.assign_local (|
             "self" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "tuple" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "tuple" |), "__new__" |),
               make_list [
-                M.get_name (| globals, "cls" |);
+                M.get_name (| globals, locals_stack, "cls" |);
                 Constant.str "(* At expr: unsupported node type: GeneratorExp *)"
               ],
               make_dict []
@@ -822,40 +860,41 @@ Definition GaloisField : Value.t :=
           |) in
           let _ := M.assert (| Compare.eq (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "self" |)
+        M.get_name (| globals, locals_stack, "self" |)
       ],
       make_dict []
     |),
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "cls" |), "MODULUS" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "MODULUS" |)
       ],
       make_dict []
     |)
   |) |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "self" |)
+            M.get_name (| globals, locals_stack, "self" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__add__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
+                  M.get_name (| globals, locals_stack, "right" |);
                   M.call (|
-                    M.get_name (| globals, "type" |),
+                    M.get_name (| globals, locals_stack, "type" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |)
@@ -865,7 +904,7 @@ Definition GaloisField : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -874,12 +913,12 @@ Definition GaloisField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -892,13 +931,14 @@ Definition GaloisField : Value.t :=
       );
       (
         "__radd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -907,13 +947,14 @@ Definition GaloisField : Value.t :=
       );
       (
         "__iadd__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__add__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__add__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -922,19 +963,20 @@ Definition GaloisField : Value.t :=
       );
       (
         "__sub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "right" |);
+                  M.get_name (| globals, locals_stack, "right" |);
                   M.call (|
-                    M.get_name (| globals, "type" |),
+                    M.get_name (| globals, locals_stack, "type" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |)
@@ -944,7 +986,7 @@ Definition GaloisField : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -955,12 +997,12 @@ Definition GaloisField : Value.t :=
 (* At stmt: unsupported node type: AnnAssign *)
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -973,19 +1015,20 @@ Definition GaloisField : Value.t :=
       );
       (
         "__rsub__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               UnOp.not (| M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "left" |);
+                  M.get_name (| globals, locals_stack, "left" |);
                   M.call (|
-                    M.get_name (| globals, "type" |),
+                    M.get_name (| globals, locals_stack, "type" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |)
@@ -995,7 +1038,7 @@ Definition GaloisField : Value.t :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "NotImplemented" |)
+                M.get_name (| globals, locals_stack, "NotImplemented" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1004,12 +1047,12 @@ Definition GaloisField : Value.t :=
             )) |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -1022,25 +1065,26 @@ Definition GaloisField : Value.t :=
       );
       (
         "__mul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.assign_local (|
             "modulus" ,
-            M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
           |) in
           let _ := M.assign_local (|
             "degree" ,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "modulus" |)
+                M.get_name (| globals, locals_stack, "modulus" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.assign_local (|
             "prime" ,
-            M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
           |) in
           let _ := M.assign_local (|
             "mul" ,
@@ -1049,29 +1093,29 @@ Definition GaloisField : Value.t :=
                 Constant.int 0
               ],
               BinOp.mult (|
-                M.get_name (| globals, "degree" |),
+                M.get_name (| globals, locals_stack, "degree" |),
                 Constant.int 2
               |)
             |)
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "degree" |)
+        M.get_name (| globals, locals_stack, "degree" |)
       ],
       make_dict []
     |),
               ltac:(M.monadic (
                 let _ :=
                   M.for_ (|
-                    M.get_name (| globals, "j" |),
+                    M.get_name (| globals, locals_stack, "j" |),
                     M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "degree" |)
+        M.get_name (| globals, locals_stack, "degree" |)
       ],
       make_dict []
     |),
@@ -1079,20 +1123,20 @@ Definition GaloisField : Value.t :=
                       let _ := M.assign_op (|
                         BinOp.add,
                         M.get_subscript (|
-    M.get_name (| globals, "mul" |),
+    M.get_name (| globals, locals_stack, "mul" |),
     BinOp.add (|
-      M.get_name (| globals, "i" |),
-      M.get_name (| globals, "j" |)
+      M.get_name (| globals, locals_stack, "i" |),
+      M.get_name (| globals, locals_stack, "j" |)
     |)
   |),
                         BinOp.mult (|
     M.get_subscript (|
-      M.get_name (| globals, "self" |),
-      M.get_name (| globals, "i" |)
+      M.get_name (| globals, locals_stack, "self" |),
+      M.get_name (| globals, locals_stack, "i" |)
     |),
     M.get_subscript (|
-      M.get_name (| globals, "right" |),
-      M.get_name (| globals, "j" |)
+      M.get_name (| globals, locals_stack, "right" |),
+      M.get_name (| globals, locals_stack, "j" |)
     |)
   |)
                       |) in
@@ -1110,19 +1154,19 @@ Definition GaloisField : Value.t :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
           BinOp.mult (|
-            M.get_name (| globals, "degree" |),
+            M.get_name (| globals, locals_stack, "degree" |),
             Constant.int 2
           |),
           Constant.int 1
         |);
         BinOp.sub (|
-          M.get_name (| globals, "degree" |),
+          M.get_name (| globals, locals_stack, "degree" |),
           Constant.int 1
         |);
         UnOp.sub (| Constant.int 1 |)
@@ -1132,15 +1176,15 @@ Definition GaloisField : Value.t :=
               ltac:(M.monadic (
                 let _ :=
                   M.for_ (|
-                    M.get_name (| globals, "j" |),
+                    M.get_name (| globals, locals_stack, "j" |),
                     M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
-          M.get_name (| globals, "i" |),
-          M.get_name (| globals, "degree" |)
+          M.get_name (| globals, locals_stack, "i" |),
+          M.get_name (| globals, locals_stack, "degree" |)
         |);
-        M.get_name (| globals, "i" |)
+        M.get_name (| globals, locals_stack, "i" |)
       ],
       make_dict []
     |),
@@ -1148,27 +1192,27 @@ Definition GaloisField : Value.t :=
                       let _ := M.assign_op (|
                         BinOp.sub,
                         M.get_subscript (|
-    M.get_name (| globals, "mul" |),
-    M.get_name (| globals, "j" |)
+    M.get_name (| globals, locals_stack, "mul" |),
+    M.get_name (| globals, locals_stack, "j" |)
   |),
                         BinOp.mod_ (|
     BinOp.mult (|
       M.get_subscript (|
-        M.get_name (| globals, "mul" |),
-        M.get_name (| globals, "i" |)
+        M.get_name (| globals, locals_stack, "mul" |),
+        M.get_name (| globals, locals_stack, "i" |)
       |),
       M.get_subscript (|
-        M.get_name (| globals, "modulus" |),
+        M.get_name (| globals, locals_stack, "modulus" |),
         BinOp.sub (|
-          M.get_name (| globals, "degree" |),
+          M.get_name (| globals, locals_stack, "degree" |),
           BinOp.sub (|
-            M.get_name (| globals, "i" |),
-            M.get_name (| globals, "j" |)
+            M.get_name (| globals, locals_stack, "i" |),
+            M.get_name (| globals, locals_stack, "j" |)
           |)
         |)
       |)
     |),
-    M.get_name (| globals, "prime" |)
+    M.get_name (| globals, locals_stack, "prime" |)
   |)
                       |) in
                       M.pure Constant.None_
@@ -1185,19 +1229,19 @@ Definition GaloisField : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
                 M.slice (|
-                  M.get_name (| globals, "mul" |),
+                  M.get_name (| globals, locals_stack, "mul" |),
                   Constant.None_,
-                  M.get_name (| globals, "degree" |),
+                  M.get_name (| globals, locals_stack, "degree" |),
                   Constant.None_
                 |)
               ],
@@ -1208,13 +1252,14 @@ Definition GaloisField : Value.t :=
       );
       (
         "__rmul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "left" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "left" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "left" |)
+                M.get_name (| globals, locals_stack, "left" |)
               ],
               make_dict []
             |)
@@ -1223,13 +1268,14 @@ Definition GaloisField : Value.t :=
       );
       (
         "__imul__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__mul__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__mul__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -1238,13 +1284,14 @@ Definition GaloisField : Value.t :=
       );
       (
         "__truediv__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             BinOp.mult (|
-              M.get_name (| globals, "self" |),
+              M.get_name (| globals, locals_stack, "self" |),
               M.call (|
-                M.get_field (| M.get_name (| globals, "right" |), "multiplicative_inverse" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "right" |), "multiplicative_inverse" |),
                 make_list [],
                 make_dict []
               |)
@@ -1254,16 +1301,17 @@ Definition GaloisField : Value.t :=
       );
       (
         "__neg__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -1276,20 +1324,21 @@ Definition GaloisField : Value.t :=
       );
       (
         "scalar_mul",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "x" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "x" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Multiply a field element by a integer. This is faster than using
         `from_int()` and field multiplication.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -1302,22 +1351,23 @@ Definition GaloisField : Value.t :=
       );
       (
         "deg",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         This is a support function for `multiplicative_inverse()`.
         " in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
             ],
             make_dict []
           |),
@@ -1334,15 +1384,15 @@ Definition GaloisField : Value.t :=
                   M.if_then_else (|
                     Compare.not_eq (|
                       M.get_subscript (|
-                        M.get_name (| globals, "self" |),
-                        M.get_name (| globals, "i" |)
+                        M.get_name (| globals, locals_stack, "self" |),
+                        M.get_name (| globals, locals_stack, "i" |)
                       |),
                       Constant.int 0
                     |),
                   (* then *)
                   ltac:(M.monadic (
                     let _ := M.return_ (|
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "i" |)
                     |) in
                     M.pure Constant.None_
                   (* else *)
@@ -1356,7 +1406,7 @@ Definition GaloisField : Value.t :=
               ))
           |) in
           let _ := M.raise (| Some (M.call (|
-            M.get_name (| globals, "ValueError" |),
+            M.get_name (| globals, locals_stack, "ValueError" |),
             make_list [
               Constant.str "deg() does not support zero"
             ],
@@ -1366,22 +1416,23 @@ Definition GaloisField : Value.t :=
       );
       (
         "multiplicative_inverse",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Calculate the multiplicative inverse. Uses the Euclidean algorithm.
         " in
 (* At stmt: unsupported node type: AnnAssign *)
           let _ := M.assign_local (|
             "p" ,
-            M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "x1" |); M.get_name (| globals, "f1" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "x1" |); M.get_name (| globals, locals_stack, "f1" |) ],
             make_tuple [ M.call (|
-              M.get_name (| globals, "list" |),
+              M.get_name (| globals, locals_stack, "list" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
               ],
               make_dict []
             |); BinOp.mult (|
@@ -1389,20 +1440,20 @@ Definition GaloisField : Value.t :=
                 Constant.int 0
               ],
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_name (| globals, "self" |)
+                  M.get_name (| globals, locals_stack, "self" |)
                 ],
                 make_dict []
               |)
             |) ]
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "x2" |); M.get_name (| globals, "f2" |); M.get_name (| globals, "d2" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "x2" |); M.get_name (| globals, locals_stack, "f2" |); M.get_name (| globals, locals_stack, "d2" |) ],
             make_tuple [ M.call (|
-              M.get_name (| globals, "list" |),
+              M.get_name (| globals, locals_stack, "list" |),
               make_list [
-                M.get_name (| globals, "self" |)
+                M.get_name (| globals, locals_stack, "self" |)
               ],
               make_dict []
             |); BinOp.add (|
@@ -1415,9 +1466,9 @@ Definition GaloisField : Value.t :=
                 ],
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "self" |)
+                      M.get_name (| globals, locals_stack, "self" |)
                     ],
                     make_dict []
                   |),
@@ -1425,7 +1476,7 @@ Definition GaloisField : Value.t :=
                 |)
               |)
             |); M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "deg" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "deg" |),
               make_list [],
               make_dict []
             |) ]
@@ -1433,119 +1484,119 @@ Definition GaloisField : Value.t :=
           let _ := M.assign_local (|
             "q_0" ,
             M.call (|
-              M.get_name (| globals, "pow" |),
+              M.get_name (| globals, locals_stack, "pow" |),
               make_list [
                 M.get_subscript (|
-                  M.get_name (| globals, "x2" |),
-                  M.get_name (| globals, "d2" |)
+                  M.get_name (| globals, locals_stack, "x2" |),
+                  M.get_name (| globals, locals_stack, "d2" |)
                 |);
                 UnOp.sub (| Constant.int 1 |);
-                M.get_name (| globals, "p" |)
+                M.get_name (| globals, locals_stack, "p" |)
               ],
               make_dict []
             |)
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "d2" |)
+        M.get_name (| globals, locals_stack, "d2" |)
       ],
       make_dict []
     |),
               ltac:(M.monadic (
                 let _ := M.assign (|
                   M.get_subscript (|
-                    M.get_name (| globals, "x1" |),
+                    M.get_name (| globals, locals_stack, "x1" |),
                     BinOp.sub (|
                       BinOp.add (|
-                        M.get_name (| globals, "i" |),
+                        M.get_name (| globals, locals_stack, "i" |),
                         M.call (|
-                          M.get_name (| globals, "len" |),
+                          M.get_name (| globals, locals_stack, "len" |),
                           make_list [
-                            M.get_name (| globals, "x1" |)
+                            M.get_name (| globals, locals_stack, "x1" |)
                           ],
                           make_dict []
                         |)
                       |),
-                      M.get_name (| globals, "d2" |)
+                      M.get_name (| globals, locals_stack, "d2" |)
                     |)
                   |),
                   BinOp.mod_ (|
                     BinOp.sub (|
                       M.get_subscript (|
-                        M.get_name (| globals, "x1" |),
+                        M.get_name (| globals, locals_stack, "x1" |),
                         BinOp.sub (|
                           BinOp.add (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             M.call (|
-                              M.get_name (| globals, "len" |),
+                              M.get_name (| globals, locals_stack, "len" |),
                               make_list [
-                                M.get_name (| globals, "x1" |)
+                                M.get_name (| globals, locals_stack, "x1" |)
                               ],
                               make_dict []
                             |)
                           |),
-                          M.get_name (| globals, "d2" |)
+                          M.get_name (| globals, locals_stack, "d2" |)
                         |)
                       |),
                       BinOp.mult (|
-                        M.get_name (| globals, "q_0" |),
+                        M.get_name (| globals, locals_stack, "q_0" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "x2" |),
-                          M.get_name (| globals, "i" |)
+                          M.get_name (| globals, locals_stack, "x2" |),
+                          M.get_name (| globals, locals_stack, "i" |)
                         |)
                       |)
                     |),
-                    M.get_name (| globals, "p" |)
+                    M.get_name (| globals, locals_stack, "p" |)
                   |)
                 |) in
                 let _ := M.assign (|
                   M.get_subscript (|
-                    M.get_name (| globals, "f1" |),
+                    M.get_name (| globals, locals_stack, "f1" |),
                     BinOp.sub (|
                       BinOp.add (|
-                        M.get_name (| globals, "i" |),
+                        M.get_name (| globals, locals_stack, "i" |),
                         M.call (|
-                          M.get_name (| globals, "len" |),
+                          M.get_name (| globals, locals_stack, "len" |),
                           make_list [
-                            M.get_name (| globals, "x1" |)
+                            M.get_name (| globals, locals_stack, "x1" |)
                           ],
                           make_dict []
                         |)
                       |),
-                      M.get_name (| globals, "d2" |)
+                      M.get_name (| globals, locals_stack, "d2" |)
                     |)
                   |),
                   BinOp.mod_ (|
                     BinOp.sub (|
                       M.get_subscript (|
-                        M.get_name (| globals, "f1" |),
+                        M.get_name (| globals, locals_stack, "f1" |),
                         BinOp.sub (|
                           BinOp.add (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             M.call (|
-                              M.get_name (| globals, "len" |),
+                              M.get_name (| globals, locals_stack, "len" |),
                               make_list [
-                                M.get_name (| globals, "x1" |)
+                                M.get_name (| globals, locals_stack, "x1" |)
                               ],
                               make_dict []
                             |)
                           |),
-                          M.get_name (| globals, "d2" |)
+                          M.get_name (| globals, locals_stack, "d2" |)
                         |)
                       |),
                       BinOp.mult (|
-                        M.get_name (| globals, "q_0" |),
+                        M.get_name (| globals, locals_stack, "q_0" |),
                         M.get_subscript (|
-                          M.get_name (| globals, "f2" |),
-                          M.get_name (| globals, "i" |)
+                          M.get_name (| globals, locals_stack, "f2" |),
+                          M.get_name (| globals, locals_stack, "i" |)
                         |)
                       |)
                     |),
-                    M.get_name (| globals, "p" |)
+                    M.get_name (| globals, locals_stack, "p" |)
                   |)
                 |) in
                 M.pure Constant.None_
@@ -1556,15 +1607,15 @@ Definition GaloisField : Value.t :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
             ],
             make_dict []
           |),
@@ -1581,8 +1632,8 @@ Definition GaloisField : Value.t :=
                   M.if_then_else (|
                     Compare.not_eq (|
                       M.get_subscript (|
-                        M.get_name (| globals, "x1" |),
-                        M.get_name (| globals, "i" |)
+                        M.get_name (| globals, locals_stack, "x1" |),
+                        M.get_name (| globals, locals_stack, "i" |)
                       |),
                       Constant.int 0
                     |),
@@ -1590,7 +1641,7 @@ Definition GaloisField : Value.t :=
                   ltac:(M.monadic (
                     let _ := M.assign_local (|
                       "d1" ,
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "i" |)
                     |) in
                     let _ := M.break (| |) in
                     M.pure Constant.None_
@@ -1612,40 +1663,40 @@ Definition GaloisField : Value.t :=
                   (* if *)
                   M.if_then_else (|
                     Compare.eq (|
-                      M.get_name (| globals, "d1" |),
+                      M.get_name (| globals, locals_stack, "d1" |),
                       Constant.int 0
                     |),
                   (* then *)
                   ltac:(M.monadic (
                     let _ := M.assign_local (|
                       "ans" ,
-                      M.get_name (| globals, "f1" |)
+                      M.get_name (| globals, locals_stack, "f1" |)
                     |) in
                     let _ := M.assign_local (|
                       "q" ,
                       M.call (|
-                        M.get_name (| globals, "pow" |),
+                        M.get_name (| globals, locals_stack, "pow" |),
                         make_list [
                           M.get_subscript (|
-                            M.get_name (| globals, "x1" |),
+                            M.get_name (| globals, locals_stack, "x1" |),
                             Constant.int 0
                           |);
                           UnOp.sub (| Constant.int 1 |);
-                          M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
                         ],
                         make_dict []
                       |)
                     |) in
                     let _ :=
                       M.for_ (|
-                        M.get_name (| globals, "i" |),
+                        M.get_name (| globals, locals_stack, "i" |),
                         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ans" |)
+            M.get_name (| globals, locals_stack, "ans" |)
           ],
           make_dict []
         |)
@@ -1656,10 +1707,10 @@ Definition GaloisField : Value.t :=
                           let _ := M.assign_op (|
                             BinOp.mult,
                             M.get_subscript (|
-    M.get_name (| globals, "ans" |),
-    M.get_name (| globals, "i" |)
+    M.get_name (| globals, locals_stack, "ans" |),
+    M.get_name (| globals, locals_stack, "i" |)
   |),
-                            M.get_name (| globals, "q" |)
+                            M.get_name (| globals, locals_stack, "q" |)
                           |) in
                           M.pure Constant.None_
                         )),
@@ -1675,40 +1726,40 @@ Definition GaloisField : Value.t :=
                       (* if *)
                       M.if_then_else (|
                         Compare.eq (|
-                          M.get_name (| globals, "d2" |),
+                          M.get_name (| globals, locals_stack, "d2" |),
                           Constant.int 0
                         |),
                       (* then *)
                       ltac:(M.monadic (
                         let _ := M.assign_local (|
                           "ans" ,
-                          M.get_name (| globals, "f2" |)
+                          M.get_name (| globals, locals_stack, "f2" |)
                         |) in
                         let _ := M.assign_local (|
                           "q" ,
                           M.call (|
-                            M.get_name (| globals, "pow" |),
+                            M.get_name (| globals, locals_stack, "pow" |),
                             make_list [
                               M.get_subscript (|
-                                M.get_name (| globals, "x2" |),
+                                M.get_name (| globals, locals_stack, "x2" |),
                                 Constant.int 0
                               |);
                               UnOp.sub (| Constant.int 1 |);
-                              M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+                              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
                             ],
                             make_dict []
                           |)
                         |) in
                         let _ :=
                           M.for_ (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ans" |)
+            M.get_name (| globals, locals_stack, "ans" |)
           ],
           make_dict []
         |)
@@ -1719,7 +1770,7 @@ Definition GaloisField : Value.t :=
                               let _ := M.assign_op_local (|
                                 BinOp.mult,
                                 "ans",
-                                M.get_name (| globals, "q" |)
+                                M.get_name (| globals, locals_stack, "q" |)
                               |) in
                               M.pure Constant.None_
                             )),
@@ -1739,8 +1790,8 @@ Definition GaloisField : Value.t :=
                   (* if *)
                   M.if_then_else (|
                     Compare.lt (|
-                      M.get_name (| globals, "d1" |),
-                      M.get_name (| globals, "d2" |)
+                      M.get_name (| globals, locals_stack, "d1" |),
+                      M.get_name (| globals, locals_stack, "d2" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
@@ -1748,18 +1799,18 @@ Definition GaloisField : Value.t :=
                       "q" ,
                       BinOp.mult (|
                         M.get_subscript (|
-                          M.get_name (| globals, "x2" |),
-                          M.get_name (| globals, "d2" |)
+                          M.get_name (| globals, locals_stack, "x2" |),
+                          M.get_name (| globals, locals_stack, "d2" |)
                         |),
                         M.call (|
-                          M.get_name (| globals, "pow" |),
+                          M.get_name (| globals, locals_stack, "pow" |),
                           make_list [
                             M.get_subscript (|
-                              M.get_name (| globals, "x1" |),
-                              M.get_name (| globals, "d1" |)
+                              M.get_name (| globals, locals_stack, "x1" |),
+                              M.get_name (| globals, locals_stack, "d1" |)
                             |);
                             UnOp.sub (| Constant.int 1 |);
-                            M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+                            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
                           ],
                           make_dict []
                         |)
@@ -1767,21 +1818,21 @@ Definition GaloisField : Value.t :=
                     |) in
                     let _ :=
                       M.for_ (|
-                        M.get_name (| globals, "i" |),
+                        M.get_name (| globals, locals_stack, "i" |),
                         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
             ],
             make_dict []
           |),
           BinOp.sub (|
-            M.get_name (| globals, "d2" |),
-            M.get_name (| globals, "d1" |)
+            M.get_name (| globals, locals_stack, "d2" |),
+            M.get_name (| globals, locals_stack, "d1" |)
           |)
         |)
       ],
@@ -1790,70 +1841,70 @@ Definition GaloisField : Value.t :=
                         ltac:(M.monadic (
                           let _ := M.assign (|
                             M.get_subscript (|
-                              M.get_name (| globals, "x2" |),
+                              M.get_name (| globals, locals_stack, "x2" |),
                               BinOp.add (|
-                                M.get_name (| globals, "i" |),
+                                M.get_name (| globals, locals_stack, "i" |),
                                 BinOp.sub (|
-                                  M.get_name (| globals, "d2" |),
-                                  M.get_name (| globals, "d1" |)
+                                  M.get_name (| globals, locals_stack, "d2" |),
+                                  M.get_name (| globals, locals_stack, "d1" |)
                                 |)
                               |)
                             |),
                             BinOp.mod_ (|
                               BinOp.sub (|
                                 M.get_subscript (|
-                                  M.get_name (| globals, "x2" |),
+                                  M.get_name (| globals, locals_stack, "x2" |),
                                   BinOp.add (|
-                                    M.get_name (| globals, "i" |),
+                                    M.get_name (| globals, locals_stack, "i" |),
                                     BinOp.sub (|
-                                      M.get_name (| globals, "d2" |),
-                                      M.get_name (| globals, "d1" |)
+                                      M.get_name (| globals, locals_stack, "d2" |),
+                                      M.get_name (| globals, locals_stack, "d1" |)
                                     |)
                                   |)
                                 |),
                                 BinOp.mult (|
-                                  M.get_name (| globals, "q" |),
+                                  M.get_name (| globals, locals_stack, "q" |),
                                   M.get_subscript (|
-                                    M.get_name (| globals, "x1" |),
-                                    M.get_name (| globals, "i" |)
+                                    M.get_name (| globals, locals_stack, "x1" |),
+                                    M.get_name (| globals, locals_stack, "i" |)
                                   |)
                                 |)
                               |),
-                              M.get_name (| globals, "p" |)
+                              M.get_name (| globals, locals_stack, "p" |)
                             |)
                           |) in
                           let _ := M.assign (|
                             M.get_subscript (|
-                              M.get_name (| globals, "f2" |),
+                              M.get_name (| globals, locals_stack, "f2" |),
                               BinOp.add (|
-                                M.get_name (| globals, "i" |),
+                                M.get_name (| globals, locals_stack, "i" |),
                                 BinOp.sub (|
-                                  M.get_name (| globals, "d2" |),
-                                  M.get_name (| globals, "d1" |)
+                                  M.get_name (| globals, locals_stack, "d2" |),
+                                  M.get_name (| globals, locals_stack, "d1" |)
                                 |)
                               |)
                             |),
                             BinOp.mod_ (|
                               BinOp.sub (|
                                 M.get_subscript (|
-                                  M.get_name (| globals, "f2" |),
+                                  M.get_name (| globals, locals_stack, "f2" |),
                                   BinOp.add (|
-                                    M.get_name (| globals, "i" |),
+                                    M.get_name (| globals, locals_stack, "i" |),
                                     BinOp.sub (|
-                                      M.get_name (| globals, "d2" |),
-                                      M.get_name (| globals, "d1" |)
+                                      M.get_name (| globals, locals_stack, "d2" |),
+                                      M.get_name (| globals, locals_stack, "d1" |)
                                     |)
                                   |)
                                 |),
                                 BinOp.mult (|
-                                  M.get_name (| globals, "q" |),
+                                  M.get_name (| globals, locals_stack, "q" |),
                                   M.get_subscript (|
-                                    M.get_name (| globals, "f1" |),
-                                    M.get_name (| globals, "i" |)
+                                    M.get_name (| globals, locals_stack, "f1" |),
+                                    M.get_name (| globals, locals_stack, "i" |)
                                   |)
                                 |)
                               |),
-                              M.get_name (| globals, "p" |)
+                              M.get_name (| globals, locals_stack, "p" |)
                             |)
                           |) in
                           M.pure Constant.None_
@@ -1866,8 +1917,8 @@ Definition GaloisField : Value.t :=
                       M.while (|
                         Compare.eq (|
       M.get_subscript (|
-        M.get_name (| globals, "x2" |),
-        M.get_name (| globals, "d2" |)
+        M.get_name (| globals, locals_stack, "x2" |),
+        M.get_name (| globals, locals_stack, "d2" |)
       |),
       Constant.int 0
     |),
@@ -1890,18 +1941,18 @@ Definition GaloisField : Value.t :=
                       "q" ,
                       BinOp.mult (|
                         M.get_subscript (|
-                          M.get_name (| globals, "x1" |),
-                          M.get_name (| globals, "d1" |)
+                          M.get_name (| globals, locals_stack, "x1" |),
+                          M.get_name (| globals, locals_stack, "d1" |)
                         |),
                         M.call (|
-                          M.get_name (| globals, "pow" |),
+                          M.get_name (| globals, locals_stack, "pow" |),
                           make_list [
                             M.get_subscript (|
-                              M.get_name (| globals, "x2" |),
-                              M.get_name (| globals, "d2" |)
+                              M.get_name (| globals, locals_stack, "x2" |),
+                              M.get_name (| globals, locals_stack, "d2" |)
                             |);
                             UnOp.sub (| Constant.int 1 |);
-                            M.get_field (| M.get_name (| globals, "self" |), "PRIME" |)
+                            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "PRIME" |)
                           ],
                           make_dict []
                         |)
@@ -1909,21 +1960,21 @@ Definition GaloisField : Value.t :=
                     |) in
                     let _ :=
                       M.for_ (|
-                        M.get_name (| globals, "i" |),
+                        M.get_name (| globals, locals_stack, "i" |),
                         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.sub (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
             ],
             make_dict []
           |),
           BinOp.sub (|
-            M.get_name (| globals, "d1" |),
-            M.get_name (| globals, "d2" |)
+            M.get_name (| globals, locals_stack, "d1" |),
+            M.get_name (| globals, locals_stack, "d2" |)
           |)
         |)
       ],
@@ -1932,70 +1983,70 @@ Definition GaloisField : Value.t :=
                         ltac:(M.monadic (
                           let _ := M.assign (|
                             M.get_subscript (|
-                              M.get_name (| globals, "x1" |),
+                              M.get_name (| globals, locals_stack, "x1" |),
                               BinOp.add (|
-                                M.get_name (| globals, "i" |),
+                                M.get_name (| globals, locals_stack, "i" |),
                                 BinOp.sub (|
-                                  M.get_name (| globals, "d1" |),
-                                  M.get_name (| globals, "d2" |)
+                                  M.get_name (| globals, locals_stack, "d1" |),
+                                  M.get_name (| globals, locals_stack, "d2" |)
                                 |)
                               |)
                             |),
                             BinOp.mod_ (|
                               BinOp.sub (|
                                 M.get_subscript (|
-                                  M.get_name (| globals, "x1" |),
+                                  M.get_name (| globals, locals_stack, "x1" |),
                                   BinOp.add (|
-                                    M.get_name (| globals, "i" |),
+                                    M.get_name (| globals, locals_stack, "i" |),
                                     BinOp.sub (|
-                                      M.get_name (| globals, "d1" |),
-                                      M.get_name (| globals, "d2" |)
+                                      M.get_name (| globals, locals_stack, "d1" |),
+                                      M.get_name (| globals, locals_stack, "d2" |)
                                     |)
                                   |)
                                 |),
                                 BinOp.mult (|
-                                  M.get_name (| globals, "q" |),
+                                  M.get_name (| globals, locals_stack, "q" |),
                                   M.get_subscript (|
-                                    M.get_name (| globals, "x2" |),
-                                    M.get_name (| globals, "i" |)
+                                    M.get_name (| globals, locals_stack, "x2" |),
+                                    M.get_name (| globals, locals_stack, "i" |)
                                   |)
                                 |)
                               |),
-                              M.get_name (| globals, "p" |)
+                              M.get_name (| globals, locals_stack, "p" |)
                             |)
                           |) in
                           let _ := M.assign (|
                             M.get_subscript (|
-                              M.get_name (| globals, "f1" |),
+                              M.get_name (| globals, locals_stack, "f1" |),
                               BinOp.add (|
-                                M.get_name (| globals, "i" |),
+                                M.get_name (| globals, locals_stack, "i" |),
                                 BinOp.sub (|
-                                  M.get_name (| globals, "d1" |),
-                                  M.get_name (| globals, "d2" |)
+                                  M.get_name (| globals, locals_stack, "d1" |),
+                                  M.get_name (| globals, locals_stack, "d2" |)
                                 |)
                               |)
                             |),
                             BinOp.mod_ (|
                               BinOp.sub (|
                                 M.get_subscript (|
-                                  M.get_name (| globals, "f1" |),
+                                  M.get_name (| globals, locals_stack, "f1" |),
                                   BinOp.add (|
-                                    M.get_name (| globals, "i" |),
+                                    M.get_name (| globals, locals_stack, "i" |),
                                     BinOp.sub (|
-                                      M.get_name (| globals, "d1" |),
-                                      M.get_name (| globals, "d2" |)
+                                      M.get_name (| globals, locals_stack, "d1" |),
+                                      M.get_name (| globals, locals_stack, "d2" |)
                                     |)
                                   |)
                                 |),
                                 BinOp.mult (|
-                                  M.get_name (| globals, "q" |),
+                                  M.get_name (| globals, locals_stack, "q" |),
                                   M.get_subscript (|
-                                    M.get_name (| globals, "f2" |),
-                                    M.get_name (| globals, "i" |)
+                                    M.get_name (| globals, locals_stack, "f2" |),
+                                    M.get_name (| globals, locals_stack, "i" |)
                                   |)
                                 |)
                               |),
-                              M.get_name (| globals, "p" |)
+                              M.get_name (| globals, locals_stack, "p" |)
                             |)
                           |) in
                           M.pure Constant.None_
@@ -2008,8 +2059,8 @@ Definition GaloisField : Value.t :=
                       M.while (|
                         Compare.eq (|
       M.get_subscript (|
-        M.get_name (| globals, "x1" |),
-        M.get_name (| globals, "d1" |)
+        M.get_name (| globals, locals_stack, "x1" |),
+        M.get_name (| globals, locals_stack, "d1" |)
       |),
       Constant.int 0
     |),
@@ -2035,16 +2086,16 @@ Definition GaloisField : Value.t :=
           |) in
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
-                M.get_name (| globals, "ans" |)
+                M.get_name (| globals, locals_stack, "ans" |)
               ],
               make_dict []
             |)
@@ -2053,14 +2104,15 @@ Definition GaloisField : Value.t :=
       );
       (
         "__pow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "exponent" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "exponent" ] in
+          ltac:(M.monadic (
           let _ := M.assign_local (|
             "degree" ,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "MODULUS" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "MODULUS" |)
               ],
               make_dict []
             |)
@@ -2069,7 +2121,7 @@ Definition GaloisField : Value.t :=
             (* if *)
             M.if_then_else (|
               Compare.lt (|
-                M.get_name (| globals, "exponent" |),
+                M.get_name (| globals, locals_stack, "exponent" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2077,14 +2129,14 @@ Definition GaloisField : Value.t :=
               let _ := M.assign_local (|
                 "self" ,
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "self" |), "multiplicative_inverse" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "multiplicative_inverse" |),
                   make_list [],
                   make_dict []
                 |)
               |) in
               let _ := M.assign_local (|
                 "exponent" ,
-                UnOp.sub (| M.get_name (| globals, "exponent" |) |)
+                UnOp.sub (| M.get_name (| globals, locals_stack, "exponent" |) |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2094,12 +2146,12 @@ Definition GaloisField : Value.t :=
           let _ := M.assign_local (|
             "res" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__new__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__new__" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "type" |),
+                  M.get_name (| globals, locals_stack, "type" |),
                   make_list [
-                    M.get_name (| globals, "self" |)
+                    M.get_name (| globals, locals_stack, "self" |)
                   ],
                   make_dict []
                 |);
@@ -2112,7 +2164,7 @@ Definition GaloisField : Value.t :=
                       Constant.int 0
                     ],
                     BinOp.sub (|
-                      M.get_name (| globals, "degree" |),
+                      M.get_name (| globals, locals_stack, "degree" |),
                       Constant.int 1
                     |)
                   |)
@@ -2123,12 +2175,12 @@ Definition GaloisField : Value.t :=
           |) in
           let _ := M.assign_local (|
             "s" ,
-            M.get_name (| globals, "self" |)
+            M.get_name (| globals, locals_stack, "self" |)
           |) in
           let _ :=
             M.while (|
               Compare.not_eq (|
-      M.get_name (| globals, "exponent" |),
+      M.get_name (| globals, locals_stack, "exponent" |),
       Constant.int 0
     |),
               ltac:(M.monadic (
@@ -2137,7 +2189,7 @@ Definition GaloisField : Value.t :=
                   M.if_then_else (|
                     Compare.eq (|
                       BinOp.mod_ (|
-                        M.get_name (| globals, "exponent" |),
+                        M.get_name (| globals, locals_stack, "exponent" |),
                         Constant.int 2
                       |),
                       Constant.int 1
@@ -2147,7 +2199,7 @@ Definition GaloisField : Value.t :=
                     let _ := M.assign_op_local (|
                       BinOp.mult,
                       "res",
-                      M.get_name (| globals, "s" |)
+                      M.get_name (| globals, locals_stack, "s" |)
                     |) in
                     M.pure Constant.None_
                   (* else *)
@@ -2157,7 +2209,7 @@ Definition GaloisField : Value.t :=
                 let _ := M.assign_op_local (|
                   BinOp.mult,
                   "s",
-                  M.get_name (| globals, "s" |)
+                  M.get_name (| globals, locals_stack, "s" |)
                 |) in
                 let _ := M.assign_op_local (|
                   BinOp.floor_div,
@@ -2171,19 +2223,20 @@ Definition GaloisField : Value.t :=
               ))
           |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "res" |)
+            M.get_name (| globals, locals_stack, "res" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__ipow__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "right" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "right" ] in
+          ltac:(M.monadic (
           let _ := M.return_ (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "__pow__" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "__pow__" |),
               make_list [
-                M.get_name (| globals, "right" |)
+                M.get_name (| globals, locals_stack, "right" |)
               ],
               make_dict []
             |)
@@ -2192,8 +2245,9 @@ Definition GaloisField : Value.t :=
       );
       (
         "frobenius",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Returns `self ** p`. This function is known as the Frobenius
         endomorphism and has many special mathematical properties. In
@@ -2203,7 +2257,7 @@ Definition GaloisField : Value.t :=
           let _ := M.assign_local (|
             "ans" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "self" |), "from_int" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "from_int" |),
               make_list [
                 Constant.int 0
               ],
@@ -2213,11 +2267,11 @@ Definition GaloisField : Value.t :=
 (* At stmt: unsupported node type: AnnAssign *)
           let _ :=
             M.for_ (|
-              make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "a" |) ],
+              make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "a" |) ],
               M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "self" |)
+        M.get_name (| globals, locals_stack, "self" |)
       ],
       make_dict []
     |),
@@ -2227,18 +2281,18 @@ Definition GaloisField : Value.t :=
                   "ans",
                   M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "cast" |),
+      M.get_name (| globals, locals_stack, "cast" |),
       make_list [
-        M.get_name (| globals, "U" |);
+        M.get_name (| globals, locals_stack, "U" |);
         M.get_subscript (|
-          M.get_field (| M.get_name (| globals, "self" |), "FROBENIUS_COEFFICIENTS" |),
-          M.get_name (| globals, "i" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "self" |), "FROBENIUS_COEFFICIENTS" |),
+          M.get_name (| globals, locals_stack, "i" |)
         |)
       ],
       make_dict []
     |), "scalar_mul" |),
     make_list [
-      M.get_name (| globals, "a" |)
+      M.get_name (| globals, locals_stack, "a" |)
     ],
     make_dict []
   |)
@@ -2250,7 +2304,7 @@ Definition GaloisField : Value.t :=
               ))
           |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "ans" |)
+            M.get_name (| globals, locals_stack, "ans" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/crypto/hash.v b/CoqOfPython/ethereum/crypto/hash.v
index ffb11bc..9f684cc 100644
--- a/CoqOfPython/ethereum/crypto/hash.v
+++ b/CoqOfPython/ethereum/crypto/hash.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.crypto.hash".
+Definition globals : Globals.t := "ethereum.crypto.hash".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,16 +30,17 @@ Axiom ethereum_base_types_imports_Bytes64 :
   IsImported globals "ethereum.base_types" "Bytes64".
 
 Definition Hash32 : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes32" |)
+  M.get_name (| globals, locals_stack, "Bytes32" |)
 )).
 
 Definition Hash64 : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes64" |)
+  M.get_name (| globals, locals_stack, "Bytes64" |)
 )).
 
 Definition keccak256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the keccak256 hash of the input `buffer`.
 
@@ -54,20 +57,20 @@ Definition keccak256 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "k" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "keccak" |), "new" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "keccak" |), "new" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
           M.call (|
             M.get_field (| M.call (|
-              M.get_field (| M.get_name (| globals, "k" |), "update" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "k" |), "update" |),
               make_list [
-                M.get_name (| globals, "buffer" |)
+                M.get_name (| globals, locals_stack, "buffer" |)
               ],
               make_dict []
             |), "digest" |),
@@ -81,8 +84,9 @@ Definition keccak256 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition keccak512 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the keccak512 hash of the input `buffer`.
 
@@ -99,20 +103,20 @@ Definition keccak512 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "k" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "keccak" |), "new" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "keccak" |), "new" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Hash64" |),
+        M.get_name (| globals, locals_stack, "Hash64" |),
         make_list [
           M.call (|
             M.get_field (| M.call (|
-              M.get_field (| M.get_name (| globals, "k" |), "update" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "k" |), "update" |),
               make_list [
-                M.get_name (| globals, "buffer" |)
+                M.get_name (| globals, locals_stack, "buffer" |)
               ],
               make_dict []
             |), "digest" |),
diff --git a/CoqOfPython/ethereum/crypto/simulations/hash.v b/CoqOfPython/ethereum/crypto/simulations/hash.v
new file mode 100644
index 0000000..f2dcfeb
--- /dev/null
+++ b/CoqOfPython/ethereum/crypto/simulations/hash.v
@@ -0,0 +1,26 @@
+Require Import CoqOfPython.CoqOfPython.
+
+Require ethereum.simulations.base_types.
+Module Bytes := base_types.Bytes.
+Module Bytes32 := base_types.Bytes32.
+Module Bytes64 := base_types.Bytes64.
+
+Module Hash32.
+  Inductive t : Set :=
+  | Make (hash : Bytes32.t).
+
+  Definition get (hash : t) : Bytes32.t :=
+    match hash with
+    | Make hash => hash
+    end.
+End Hash32.
+
+Module Hash64.
+  Inductive t : Set :=
+  | Make (hash : Bytes64.t).
+
+  Definition get (hash : t) : Bytes64.t :=
+    match hash with
+    | Make hash => hash
+    end.
+End Hash64.
diff --git a/CoqOfPython/ethereum/dao_fork/__init__.v b/CoqOfPython/ethereum/dao_fork/__init__.v
index 12b0f7a..616799d 100644
--- a/CoqOfPython/ethereum/dao_fork/__init__.v
+++ b/CoqOfPython/ethereum/dao_fork/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.__init__".
+Definition globals : Globals.t := "ethereum.dao_fork.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 1920000
     ],
diff --git a/CoqOfPython/ethereum/dao_fork/blocks.v b/CoqOfPython/ethereum/dao_fork/blocks.v
index 0707efe..ddecfb8 100644
--- a/CoqOfPython/ethereum/dao_fork/blocks.v
+++ b/CoqOfPython/ethereum/dao_fork/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.blocks".
+Definition globals : Globals.t := "ethereum.dao_fork.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/dao_fork/bloom.v b/CoqOfPython/ethereum/dao_fork/bloom.v
index 4b83130..59b1869 100644
--- a/CoqOfPython/ethereum/dao_fork/bloom.v
+++ b/CoqOfPython/ethereum/dao_fork/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.bloom".
+Definition globals : Globals.t := "ethereum.dao_fork.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_dao_fork_fork_types_imports_Bloom :
   IsImported globals "ethereum.dao_fork.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/dao.v b/CoqOfPython/ethereum/dao_fork/dao.v
index 160f310..434d57c 100644
--- a/CoqOfPython/ethereum/dao_fork/dao.v
+++ b/CoqOfPython/ethereum/dao_fork/dao.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.dao".
+Definition globals : Globals.t := "ethereum.dao_fork.dao".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,7 +38,7 @@ Definition DAO_ACCOUNTS : Value.t := M.run ltac:(M.monadic (
 
 Definition DAO_RECOVERY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0xbf4ed7b27f1d666546e30d74d50d173d20bca754"
     ],
@@ -45,8 +47,9 @@ Definition DAO_RECOVERY : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition apply_dao : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Apply the dao fork to the state.
 
@@ -57,27 +60,27 @@ Definition apply_dao : Value.t -> Value.t -> M :=
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_name (| globals, "DAO_ACCOUNTS" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_name (| globals, locals_stack, "DAO_ACCOUNTS" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "balance" ,
             M.get_field (| M.call (|
-              M.get_name (| globals, "get_account" |),
+              M.get_name (| globals, locals_stack, "get_account" |),
               make_list [
-                M.get_name (| globals, "state" |);
-                M.get_name (| globals, "address" |)
+                M.get_name (| globals, locals_stack, "state" |);
+                M.get_name (| globals, locals_stack, "address" |)
               ],
               make_dict []
             |), "balance" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "DAO_RECOVERY" |);
-      M.get_name (| globals, "balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "DAO_RECOVERY" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/dao_fork/fork.v b/CoqOfPython/ethereum/dao_fork/fork.v
index cd0c092..4f769f4 100644
--- a/CoqOfPython/ethereum/dao_fork/fork.v
+++ b/CoqOfPython/ethereum/dao_fork/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.fork".
+Definition globals : Globals.t := "ethereum.dao_fork.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -141,7 +143,7 @@ Axiom ethereum_dao_fork_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 5,
@@ -165,7 +167,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -188,8 +190,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -216,20 +219,21 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "apply_dao" |),
+    M.get_name (| globals, locals_stack, "apply_dao" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "old" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "old" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -252,7 +256,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -263,9 +267,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -287,17 +291,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -310,13 +314,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -327,20 +331,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -365,110 +370,110 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -477,9 +482,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -488,9 +493,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -504,8 +509,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -524,95 +530,95 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -621,13 +627,13 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -636,14 +642,14 @@ Definition validate_header : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.gt_e (|
-            M.get_field (| M.get_name (| globals, "header" |), "number" |),
-            M.get_field (| M.get_name (| globals, "FORK_CRITERIA" |), "block_number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "FORK_CRITERIA" |), "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.lt (|
-              M.get_field (| M.get_name (| globals, "header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
               BinOp.add (|
-                M.get_field (| M.get_name (| globals, "FORK_CRITERIA" |), "block_number" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "FORK_CRITERIA" |), "block_number" |),
                 Constant.int 10
               |)
             |)
@@ -652,13 +658,13 @@ Definition validate_header : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |),
         Constant.bytes "64616f2d686172642d666f726b"
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -668,17 +674,18 @@ Definition validate_header : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -704,26 +711,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -731,8 +738,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -750,9 +758,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -760,25 +768,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -787,41 +795,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -843,34 +852,35 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -894,13 +904,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -915,8 +925,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -957,50 +968,50 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |)
               ],
               make_dict []
             |)
@@ -1008,18 +1019,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1027,55 +1038,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
+                M.get_name (| globals, locals_stack, "tx" |);
                 M.call (|
-                  M.get_name (| globals, "state_root" |),
+                  M.get_name (| globals, locals_stack, "state_root" |),
                   make_list [
-                    M.get_name (| globals, "state" |)
+                    M.get_name (| globals, locals_stack, "state" |)
                   ],
                   make_dict []
                 |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1084,56 +1095,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1144,8 +1155,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1170,27 +1182,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1199,9 +1211,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1219,46 +1231,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1269,19 +1281,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1290,23 +1302,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1314,16 +1326,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1337,13 +1349,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1358,11 +1370,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1370,88 +1382,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1464,8 +1476,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1494,44 +1507,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1543,19 +1556,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1568,8 +1581,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1597,30 +1611,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1628,98 +1642,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1727,10 +1741,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1738,20 +1752,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1760,10 +1774,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1771,41 +1785,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1813,35 +1827,35 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1852,13 +1866,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1887,17 +1902,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1912,8 +1927,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1942,14 +1958,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1957,7 +1973,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1965,7 +1981,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -1979,9 +1995,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -1992,7 +2008,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2005,14 +2021,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2021,8 +2037,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2043,84 +2060,84 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           Constant.int 27
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 28
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "public_key" ,
       M.call (|
-        M.get_name (| globals, "secp256k1_recover" |),
+        M.get_name (| globals, locals_stack, "secp256k1_recover" |),
         make_list [
-          M.get_name (| globals, "r" |);
-          M.get_name (| globals, "s" |);
+          M.get_name (| globals, locals_stack, "r" |);
+          M.get_name (| globals, locals_stack, "s" |);
           BinOp.sub (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |);
           M.call (|
-            M.get_name (| globals, "signing_hash" |),
+            M.get_name (| globals, locals_stack, "signing_hash" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |)
@@ -2130,13 +2147,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2151,8 +2168,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in the signature.
 
@@ -2172,12 +2190,12 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2188,8 +2206,9 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2223,12 +2242,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2239,8 +2258,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2271,18 +2291,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2299,10 +2319,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2319,8 +2339,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2338,8 +2358,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2381,26 +2402,26 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
               Constant.int 1,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2418,13 +2439,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2432,9 +2453,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.sub (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |),
@@ -2447,7 +2468,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2457,7 +2478,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2467,13 +2488,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/dao_fork/fork_types.v b/CoqOfPython/ethereum/dao_fork/fork_types.v
index 7d58b79..b3f985f 100644
--- a/CoqOfPython/ethereum/dao_fork/fork_types.v
+++ b/CoqOfPython/ethereum/dao_fork/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.fork_types".
+Definition globals : Globals.t := "ethereum.dao_fork.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/dao_fork/state.v b/CoqOfPython/ethereum/dao_fork/state.v
index c526dbf..5204480 100644
--- a/CoqOfPython/ethereum/dao_fork/state.v
+++ b/CoqOfPython/ethereum/dao_fork/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.state".
+Definition globals : Globals.t := "ethereum.dao_fork.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,28 +710,29 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -724,36 +742,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -770,19 +790,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -798,21 +819,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -824,8 +845,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -839,19 +861,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -868,19 +891,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -895,11 +919,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/dao_fork/transactions.v b/CoqOfPython/ethereum/dao_fork/transactions.v
index c515aad..3da1347 100644
--- a/CoqOfPython/ethereum/dao_fork/transactions.v
+++ b/CoqOfPython/ethereum/dao_fork/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.transactions".
+Definition globals : Globals.t := "ethereum.dao_fork.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/dao_fork/trie.v b/CoqOfPython/ethereum/dao_fork/trie.v
index 77ab51e..b30178b 100644
--- a/CoqOfPython/ethereum/dao_fork/trie.v
+++ b/CoqOfPython/ethereum/dao_fork/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.trie".
+Definition globals : Globals.t := "ethereum.dao_fork.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_dao_fork_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/utils/__init__.v b/CoqOfPython/ethereum/dao_fork/utils/__init__.v
index dbf11fc..f7904df 100644
--- a/CoqOfPython/ethereum/dao_fork/utils/__init__.v
+++ b/CoqOfPython/ethereum/dao_fork/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.utils.__init__".
+Definition globals : Globals.t := "ethereum.dao_fork.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/dao_fork/utils/address.v b/CoqOfPython/ethereum/dao_fork/utils/address.v
index 43700aa..eb0718c 100644
--- a/CoqOfPython/ethereum/dao_fork/utils/address.v
+++ b/CoqOfPython/ethereum/dao_fork/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.utils.address".
+Definition globals : Globals.t := "ethereum.dao_fork.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,8 +40,9 @@ Axiom ethereum_dao_fork_fork_types_imports_Address :
   IsImported globals "ethereum.dao_fork.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -55,11 +58,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -74,8 +77,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -95,14 +99,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -114,7 +118,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -123,9 +127,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -133,9 +137,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/utils/hexadecimal.v b/CoqOfPython/ethereum/dao_fork/utils/hexadecimal.v
index 3f19f3d..c421859 100644
--- a/CoqOfPython/ethereum/dao_fork/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/dao_fork/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.dao_fork.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_dao_fork_fork_types_imports_Root :
   IsImported globals "ethereum.dao_fork.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/dao_fork/utils/message.v b/CoqOfPython/ethereum/dao_fork/utils/message.v
index 9520a0a..c21cee2 100644
--- a/CoqOfPython/ethereum/dao_fork/utils/message.v
+++ b/CoqOfPython/ethereum/dao_fork/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.utils.message".
+Definition globals : Globals.t := "ethereum.dao_fork.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,8 +48,9 @@ Axiom ethereum_dao_fork_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.dao_fork.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -81,10 +84,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -93,20 +96,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -120,7 +123,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -129,7 +132,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -138,10 +141,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -149,19 +152,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -170,14 +173,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -188,7 +191,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -200,7 +203,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/vm/__init__.v b/CoqOfPython/ethereum/dao_fork/vm/__init__.v
index 7a3276a..26cdbbe 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/__init__.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.__init__".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,8 +90,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -102,24 +105,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -132,7 +136,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/exceptions.v b/CoqOfPython/ethereum/dao_fork/vm/exceptions.v
index 193cc22..8544beb 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/exceptions.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.exceptions".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -69,22 +71,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/dao_fork/vm/gas.v b/CoqOfPython/ethereum/dao_fork/vm/gas.v
index 7739073..5fa4e93 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/gas.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.gas".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -54,7 +56,7 @@ Axiom ethereum_dao_fork_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -64,7 +66,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -74,7 +76,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -84,7 +86,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -94,7 +96,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -104,7 +106,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -114,7 +116,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -124,7 +126,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -134,7 +136,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -144,7 +146,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -154,7 +156,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -164,7 +166,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -174,7 +176,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -184,7 +186,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -194,7 +196,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -204,7 +206,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -214,7 +216,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -224,7 +226,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -234,7 +236,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -244,7 +246,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -254,7 +256,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -264,7 +266,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -274,7 +276,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -284,7 +286,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -294,7 +296,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -304,7 +306,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 40
     ],
@@ -314,7 +316,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -324,7 +326,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -334,7 +336,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -344,7 +346,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -354,7 +356,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -364,7 +366,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -374,7 +376,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -384,7 +386,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -394,7 +396,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -404,7 +406,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -414,7 +416,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -443,8 +445,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -457,13 +460,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -474,22 +477,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -499,8 +502,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -520,9 +524,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -532,15 +536,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -549,16 +553,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -577,7 +582,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -587,7 +592,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -597,12 +602,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -612,14 +617,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -633,9 +638,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -643,20 +648,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -669,8 +674,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -684,16 +689,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -701,9 +706,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -712,13 +717,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -728,10 +733,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -739,8 +744,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "gas"; "to"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "gas"; "to"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount for executing Opcodes `CALL` and `CALLCODE`.
 
@@ -764,17 +770,17 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "to" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "to" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -782,7 +788,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -790,13 +796,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -804,7 +810,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -812,12 +818,12 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "gas" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "gas" |)
           |),
-          M.get_name (| globals, "create_gas_cost" |)
+          M.get_name (| globals, locals_stack, "create_gas_cost" |)
         |),
-        M.get_name (| globals, "transfer_gas_cost" |)
+        M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -825,26 +831,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
-M.get_name (| globals, "gas" |)
+M.get_name (| globals, locals_stack, "gas" |)
       (* else *)
       )), ltac:(M.monadic (
 BinOp.add (|
-          M.get_name (| globals, "GAS_CALL_STIPEND" |),
-          M.get_name (| globals, "gas" |)
+          M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |)
       )) |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
-          M.get_name (| globals, "cost" |);
-          M.get_name (| globals, "stipend" |)
+          M.get_name (| globals, locals_stack, "cost" |);
+          M.get_name (| globals, locals_stack, "stipend" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/__init__.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/__init__.v
index ca3f554..e8eadb1 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/arithmetic.v
index c64126f..df4766a 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/bitwise.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/bitwise.v
index fccfa0d..4e056ea 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/block.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/block.v
index 5a65267..6cf1947 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/comparison.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/comparison.v
index 48940ed..d8563d6 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/control_flow.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/control_flow.v
index 2242d7f..9eaff64 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/environment.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/environment.v
index 42b1678..9c28d5a 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -60,8 +62,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -73,21 +76,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -96,14 +99,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -116,12 +120,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -130,42 +134,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -178,21 +183,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -201,14 +206,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -220,21 +226,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -243,14 +249,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -262,31 +269,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -300,30 +308,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -334,13 +342,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -349,14 +357,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -368,24 +377,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -397,14 +406,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -420,9 +430,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +440,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +450,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -451,12 +461,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -469,76 +479,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -550,24 +561,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -579,14 +590,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -602,9 +614,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -612,9 +624,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -622,9 +634,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -633,12 +645,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -651,76 +663,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -732,21 +745,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -755,14 +768,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -775,12 +789,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -789,26 +803,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -820,23 +834,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -849,12 +864,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -865,9 +880,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -875,9 +890,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -885,9 +900,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -896,12 +911,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -914,52 +929,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -967,27 +982,27 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/keccak.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/keccak.v
index 3205868..5d1d7bb 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/log.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/log.v
index 47d5c73..04aa853 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_pop :
   IsImported globals "ethereum.dao_fork.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -66,9 +69,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -89,11 +92,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -102,9 +105,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -113,9 +116,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -128,74 +131,74 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -203,9 +206,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -213,9 +216,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -223,9 +226,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -233,9 +236,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/memory.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/memory.v
index 45dbf56..7d3e36c 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/stack.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/stack.v
index 2ee7ab3..c196941 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_dao_fork_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.dao_fork.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/storage.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/storage.v
index de11f5d..7039b79 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,8 +44,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -58,9 +61,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -69,43 +72,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -119,9 +123,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -132,9 +136,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,11 +146,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -156,12 +160,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -170,14 +174,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -186,12 +190,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -200,8 +204,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -209,26 +213,26 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/instructions/system.v b/CoqOfPython/ethereum/dao_fork/vm/instructions/system.v
index 47ad133..c356eeb 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_dao_fork_vm_stack_imports_push :
   IsImported globals "ethereum.dao_fork.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -90,9 +93,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -100,9 +103,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -110,9 +113,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,35 +123,35 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -157,23 +160,23 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -181,14 +184,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -201,15 +204,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -225,10 +228,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -237,11 +240,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -252,8 +255,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -262,29 +265,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -299,27 +302,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -327,10 +330,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -338,23 +341,23 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -367,21 +370,21 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -396,14 +399,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -415,9 +419,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -425,9 +429,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -435,57 +439,58 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
@@ -495,24 +500,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -532,11 +537,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -544,10 +549,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -555,7 +560,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -563,10 +568,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -574,23 +579,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -603,19 +608,19 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -629,16 +634,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -650,14 +655,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -666,8 +671,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -679,12 +685,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -695,12 +701,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -711,9 +717,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -721,9 +727,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -731,9 +737,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -741,9 +747,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -751,9 +757,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -761,12 +767,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -775,42 +781,42 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -819,17 +825,17 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -840,26 +846,26 @@ Definition call : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -867,14 +873,15 @@ Definition call : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -886,12 +893,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -902,12 +909,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -918,9 +925,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -928,9 +935,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -938,9 +945,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -948,9 +955,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -958,26 +965,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -986,42 +993,42 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1030,17 +1037,17 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1051,26 +1058,26 @@ Definition callcode : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1078,14 +1085,15 @@ Definition callcode : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1097,12 +1105,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1112,37 +1120,37 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_ZERO" |)
+      M.get_name (| globals, locals_stack, "GAS_ZERO" |)
     |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1154,15 +1162,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1170,20 +1178,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1191,33 +1199,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1227,22 +1235,23 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1254,12 +1263,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1270,12 +1279,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1286,9 +1295,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1296,9 +1305,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,59 +1335,59 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CALL" |),
-          M.get_name (| globals, "gas" |)
+          M.get_name (| globals, locals_stack, "GAS_CALL" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/interpreter.v b/CoqOfPython/ethereum/dao_fork/vm/interpreter.v
index 1a01d75..1c5a366 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/interpreter.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.interpreter".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,7 +111,7 @@ Axiom ethereum_dao_fork_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -128,8 +130,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -151,9 +154,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -165,10 +168,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -176,39 +179,39 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -222,10 +225,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -238,10 +241,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -251,14 +254,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -266,7 +269,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -278,44 +281,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -323,8 +326,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -341,19 +345,19 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -361,24 +365,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -386,22 +390,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -421,13 +426,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -439,17 +444,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -457,10 +462,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -468,12 +473,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -485,10 +490,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -496,13 +501,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -510,22 +515,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -543,14 +549,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -558,13 +564,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/memory.v b/CoqOfPython/ethereum/dao_fork/vm/memory.v
index d512649..ea3e10e 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/memory.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.memory".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/__init__.v
index a28f1e8..659ca47 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ecrecover.v
index 0c4b624..48739c7 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_dao_fork_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.dao_fork.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/identity.v
index 4b71893..1355def 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_dao_fork_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.dao_fork.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/mapping.v
index b94fbd8..97f6101 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ripemd160.v
index 39c8265..df73567 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_dao_fork_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.dao_fork.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/sha256.v
index 69f489f..db2377c 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_dao_fork_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.dao_fork.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/dao_fork/vm/runtime.v b/CoqOfPython/ethereum/dao_fork/vm/runtime.v
index 9c619f3..acf2069 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/runtime.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.runtime".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_dao_fork_vm_instructions_imports_Ops :
   IsImported globals "ethereum.dao_fork.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/dao_fork/vm/stack.v b/CoqOfPython/ethereum/dao_fork/vm/stack.v
index b8cc90b..67bc666 100644
--- a/CoqOfPython/ethereum/dao_fork/vm/stack.v
+++ b/CoqOfPython/ethereum/dao_fork/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.dao_fork.vm.stack".
+Definition globals : Globals.t := "ethereum.dao_fork.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_dao_fork_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.dao_fork.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/ethash.v b/CoqOfPython/ethereum/ethash.v
index 59371c7..92b7c5f 100644
--- a/CoqOfPython/ethereum/ethash.v
+++ b/CoqOfPython/ethereum/ethash.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.ethash".
+Definition globals : Globals.t := "ethereum.ethash".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -194,8 +196,9 @@ Number of accesses in the [`hashimoto`] loop.
 ".
 
 Definition epoch : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the epoch number to which the block identified by `block_number`
     belongs. The first epoch is numbered zero.
@@ -209,15 +212,16 @@ Definition epoch : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.floor_div (|
-        M.get_name (| globals, "block_number" |),
-        M.get_name (| globals, "EPOCH_SIZE" |)
+        M.get_name (| globals, locals_stack, "block_number" |),
+        M.get_name (| globals, locals_stack, "EPOCH_SIZE" |)
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition cache_size : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the cache size (in bytes) of the epoch to which `block_number`
     belongs.
@@ -238,13 +242,13 @@ Definition cache_size : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       BinOp.add (|
-        M.get_name (| globals, "INITIAL_CACHE_SIZE" |),
+        M.get_name (| globals, locals_stack, "INITIAL_CACHE_SIZE" |),
         BinOp.mult (|
-          M.get_name (| globals, "CACHE_EPOCH_GROWTH_SIZE" |),
+          M.get_name (| globals, locals_stack, "CACHE_EPOCH_GROWTH_SIZE" |),
           M.call (|
-            M.get_name (| globals, "epoch" |),
+            M.get_name (| globals, locals_stack, "epoch" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |)
@@ -254,16 +258,16 @@ Definition cache_size : Value.t -> Value.t -> M :=
     let _ := M.assign_op_local (|
       BinOp.sub,
       "size",
-      M.get_name (| globals, "HASH_BYTES" |)
+      M.get_name (| globals, locals_stack, "HASH_BYTES" |)
     |) in
     let _ :=
       M.while (|
         UnOp.not (| M.call (|
-      M.get_name (| globals, "is_prime" |),
+      M.get_name (| globals, locals_stack, "is_prime" |),
       make_list [
         BinOp.floor_div (|
-          M.get_name (| globals, "size" |),
-          M.get_name (| globals, "HASH_BYTES" |)
+          M.get_name (| globals, locals_stack, "size" |),
+          M.get_name (| globals, locals_stack, "HASH_BYTES" |)
         |)
       ],
       make_dict []
@@ -274,7 +278,7 @@ Definition cache_size : Value.t -> Value.t -> M :=
             "size",
             BinOp.mult (|
     Constant.int 2,
-    M.get_name (| globals, "HASH_BYTES" |)
+    M.get_name (| globals, locals_stack, "HASH_BYTES" |)
   |)
           |) in
           M.pure Constant.None_
@@ -284,13 +288,14 @@ Definition cache_size : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "size" |)
+      M.get_name (| globals, locals_stack, "size" |)
     |) in
     M.pure Constant.None_)).
 
 Definition dataset_size : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the dataset size (in bytes) of the epoch to which `block_number`
     belongs.
@@ -313,13 +318,13 @@ Definition dataset_size : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       BinOp.add (|
-        M.get_name (| globals, "INITIAL_DATASET_SIZE" |),
+        M.get_name (| globals, locals_stack, "INITIAL_DATASET_SIZE" |),
         BinOp.mult (|
-          M.get_name (| globals, "DATASET_EPOCH_GROWTH_SIZE" |),
+          M.get_name (| globals, locals_stack, "DATASET_EPOCH_GROWTH_SIZE" |),
           M.call (|
-            M.get_name (| globals, "epoch" |),
+            M.get_name (| globals, locals_stack, "epoch" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |)
@@ -329,16 +334,16 @@ Definition dataset_size : Value.t -> Value.t -> M :=
     let _ := M.assign_op_local (|
       BinOp.sub,
       "size",
-      M.get_name (| globals, "MIX_BYTES" |)
+      M.get_name (| globals, locals_stack, "MIX_BYTES" |)
     |) in
     let _ :=
       M.while (|
         UnOp.not (| M.call (|
-      M.get_name (| globals, "is_prime" |),
+      M.get_name (| globals, locals_stack, "is_prime" |),
       make_list [
         BinOp.floor_div (|
-          M.get_name (| globals, "size" |),
-          M.get_name (| globals, "MIX_BYTES" |)
+          M.get_name (| globals, locals_stack, "size" |),
+          M.get_name (| globals, locals_stack, "MIX_BYTES" |)
         |)
       ],
       make_dict []
@@ -349,7 +354,7 @@ Definition dataset_size : Value.t -> Value.t -> M :=
             "size",
             BinOp.mult (|
     Constant.int 2,
-    M.get_name (| globals, "MIX_BYTES" |)
+    M.get_name (| globals, locals_stack, "MIX_BYTES" |)
   |)
           |) in
           M.pure Constant.None_
@@ -359,13 +364,14 @@ Definition dataset_size : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "size" |)
+      M.get_name (| globals, locals_stack, "size" |)
     |) in
     M.pure Constant.None_)).
 
 Definition generate_seed : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the cache generation seed for the block identified by
     `block_number`. See [`generate_cache`].
@@ -375,9 +381,9 @@ Definition generate_seed : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "epoch_number" ,
       M.call (|
-        M.get_name (| globals, "epoch" |),
+        M.get_name (| globals, locals_stack, "epoch" |),
         make_list [
-          M.get_name (| globals, "block_number" |)
+          M.get_name (| globals, locals_stack, "block_number" |)
         ],
         make_dict []
       |)
@@ -392,16 +398,16 @@ Definition generate_seed : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.not_eq (|
-      M.get_name (| globals, "epoch_number" |),
+      M.get_name (| globals, locals_stack, "epoch_number" |),
       Constant.int 0
     |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "seed" ,
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "seed" |)
+                M.get_name (| globals, locals_stack, "seed" |)
               ],
               make_dict []
             |)
@@ -419,9 +425,9 @@ Definition generate_seed : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "seed" |)
+          M.get_name (| globals, locals_stack, "seed" |)
         ],
         make_dict []
       |)
@@ -429,8 +435,9 @@ Definition generate_seed : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition generate_cache : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate the cache for the block identified by `block_number`. See
     [`generate_dataset`] for how the cache is used.
@@ -446,9 +453,9 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "seed" ,
       M.call (|
-        M.get_name (| globals, "generate_seed" |),
+        M.get_name (| globals, locals_stack, "generate_seed" |),
         make_list [
-          M.get_name (| globals, "block_number" |)
+          M.get_name (| globals, locals_stack, "block_number" |)
         ],
         make_dict []
       |)
@@ -456,9 +463,9 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache_size_bytes" ,
       M.call (|
-        M.get_name (| globals, "cache_size" |),
+        M.get_name (| globals, locals_stack, "cache_size" |),
         make_list [
-          M.get_name (| globals, "block_number" |)
+          M.get_name (| globals, locals_stack, "block_number" |)
         ],
         make_dict []
       |)
@@ -466,17 +473,17 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache_size_words" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "cache_size_bytes" |),
-        M.get_name (| globals, "HASH_BYTES" |)
+        M.get_name (| globals, locals_stack, "cache_size_bytes" |),
+        M.get_name (| globals, locals_stack, "HASH_BYTES" |)
       |)
     |) in
     let _ := M.assign_local (|
       "cache" ,
       make_list [
         M.call (|
-          M.get_name (| globals, "keccak512" |),
+          M.get_name (| globals, locals_stack, "keccak512" |),
           make_list [
-            M.get_name (| globals, "seed" |)
+            M.get_name (| globals, locals_stack, "seed" |)
           ],
           make_dict []
         |)
@@ -484,12 +491,12 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "index" |),
+        M.get_name (| globals, locals_stack, "index" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
-        M.get_name (| globals, "cache_size_words" |)
+        M.get_name (| globals, locals_stack, "cache_size_words" |)
       ],
       make_dict []
     |),
@@ -497,12 +504,12 @@ Definition generate_cache : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "cache_item" ,
             M.call (|
-              M.get_name (| globals, "keccak512" |),
+              M.get_name (| globals, locals_stack, "keccak512" |),
               make_list [
                 M.get_subscript (|
-                  M.get_name (| globals, "cache" |),
+                  M.get_name (| globals, locals_stack, "cache" |),
                   BinOp.sub (|
-                    M.get_name (| globals, "index" |),
+                    M.get_name (| globals, locals_stack, "index" |),
                     Constant.int 1
                   |)
                 |)
@@ -511,9 +518,9 @@ Definition generate_cache : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "cache" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "cache" |), "append" |),
     make_list [
-      M.get_name (| globals, "cache_item" |)
+      M.get_name (| globals, locals_stack, "cache_item" |)
     ],
     make_dict []
   |) in
@@ -525,22 +532,22 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "CACHE_ROUNDS" |)
+        M.get_name (| globals, locals_stack, "CACHE_ROUNDS" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "index" |),
+              M.get_name (| globals, locals_stack, "index" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "cache_size_words" |)
+        M.get_name (| globals, locals_stack, "cache_size_words" |)
       ],
       make_dict []
     |),
@@ -548,37 +555,37 @@ Definition generate_cache : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "first_cache_item" ,
                   M.get_subscript (|
-                    M.get_name (| globals, "cache" |),
+                    M.get_name (| globals, locals_stack, "cache" |),
                     BinOp.mod_ (|
                       BinOp.add (|
                         BinOp.sub (|
-                          M.get_name (| globals, "index" |),
+                          M.get_name (| globals, locals_stack, "index" |),
                           Constant.int 1
                         |),
                         M.call (|
-                          M.get_name (| globals, "int" |),
+                          M.get_name (| globals, locals_stack, "int" |),
                           make_list [
-                            M.get_name (| globals, "cache_size_words" |)
+                            M.get_name (| globals, locals_stack, "cache_size_words" |)
                           ],
                           make_dict []
                         |)
                       |),
-                      M.get_name (| globals, "cache_size_words" |)
+                      M.get_name (| globals, locals_stack, "cache_size_words" |)
                     |)
                   |)
                 |) in
                 let _ := M.assign_local (|
                   "second_cache_item" ,
                   M.get_subscript (|
-                    M.get_name (| globals, "cache" |),
+                    M.get_name (| globals, locals_stack, "cache" |),
                     BinOp.mod_ (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "U32" |), "from_le_bytes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "U32" |), "from_le_bytes" |),
                         make_list [
                           M.slice (|
                             M.get_subscript (|
-                              M.get_name (| globals, "cache" |),
-                              M.get_name (| globals, "index" |)
+                              M.get_name (| globals, locals_stack, "cache" |),
+                              M.get_name (| globals, locals_stack, "index" |)
                             |),
                             Constant.int 0,
                             Constant.int 4,
@@ -587,14 +594,14 @@ Definition generate_cache : Value.t -> Value.t -> M :=
                         ],
                         make_dict []
                       |),
-                      M.get_name (| globals, "cache_size_words" |)
+                      M.get_name (| globals, locals_stack, "cache_size_words" |)
                     |)
                   |)
                 |) in
                 let _ := M.assign_local (|
                   "result" ,
                   M.call (|
-                    M.get_name (| globals, "bytes" |),
+                    M.get_name (| globals, locals_stack, "bytes" |),
                     make_list [
                       Constant.str "(* At expr: unsupported node type: ListComp *)"
                     ],
@@ -603,13 +610,13 @@ Definition generate_cache : Value.t -> Value.t -> M :=
                 |) in
                 let _ := M.assign (|
                   M.get_subscript (|
-                    M.get_name (| globals, "cache" |),
-                    M.get_name (| globals, "index" |)
+                    M.get_name (| globals, locals_stack, "cache" |),
+                    M.get_name (| globals, locals_stack, "index" |)
                   |),
                   M.call (|
-                    M.get_name (| globals, "keccak512" |),
+                    M.get_name (| globals, locals_stack, "keccak512" |),
                     make_list [
-                      M.get_name (| globals, "result" |)
+                      M.get_name (| globals, locals_stack, "result" |)
                     ],
                     make_dict []
                   |)
@@ -628,7 +635,7 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "tuple" |),
+        M.get_name (| globals, locals_stack, "tuple" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: GeneratorExp *)"
         ],
@@ -638,8 +645,9 @@ Definition generate_cache : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition fnv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     A non-associative substitute for XOR, inspired by the [FNV] hash by Fowler,
     Noll, and Vo. See [`fnv_hash`], [`generate_dataset_item`], and
@@ -661,30 +669,30 @@ Definition fnv : Value.t -> Value.t -> M :=
         BinOp.bit_xor (|
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "a" |)
+                M.get_name (| globals, locals_stack, "a" |)
               ],
               make_dict []
             |),
             Constant.int 16777619
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "b" |)
+              M.get_name (| globals, locals_stack, "b" |)
             ],
             make_dict []
           |)
         |),
-        M.get_field (| M.get_name (| globals, "U32" |), "MAX_VALUE" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "U32" |), "MAX_VALUE" |)
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "U32" |),
+        M.get_name (| globals, locals_stack, "U32" |),
         make_list [
-          M.get_name (| globals, "result" |)
+          M.get_name (| globals, locals_stack, "result" |)
         ],
         make_dict []
       |)
@@ -692,8 +700,9 @@ Definition fnv : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition fnv_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "mix_integers"; "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "mix_integers"; "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Combines `data` into `mix_integers` using [`fnv`]. See [`hashimoto`] and
     [`generate_dataset_item`].
@@ -704,7 +713,7 @@ Definition fnv_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "tuple" |),
+        M.get_name (| globals, locals_stack, "tuple" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: GeneratorExp *)"
         ],
@@ -714,8 +723,9 @@ Definition fnv_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition generate_dataset_item : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "cache"; "index" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "cache"; "index" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate a particular dataset item 0-indexed by `index` by hashing
     pseudorandomly-selected entries from `cache` together. See [`fnv`] and
@@ -731,21 +741,21 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "mix" ,
       M.call (|
-        M.get_name (| globals, "keccak512" |),
+        M.get_name (| globals, locals_stack, "keccak512" |),
         make_list [
           M.call (|
             M.get_field (| BinOp.bit_xor (|
               M.call (|
-                M.get_name (| globals, "le_uint32_sequence_to_uint" |),
+                M.get_name (| globals, locals_stack, "le_uint32_sequence_to_uint" |),
                 make_list [
                   M.get_subscript (|
-                    M.get_name (| globals, "cache" |),
+                    M.get_name (| globals, locals_stack, "cache" |),
                     BinOp.mod_ (|
-                      M.get_name (| globals, "index" |),
+                      M.get_name (| globals, locals_stack, "index" |),
                       M.call (|
-                        M.get_name (| globals, "len" |),
+                        M.get_name (| globals, locals_stack, "len" |),
                         make_list [
-                          M.get_name (| globals, "cache" |)
+                          M.get_name (| globals, locals_stack, "cache" |)
                         ],
                         make_dict []
                       |)
@@ -754,7 +764,7 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
                 ],
                 make_dict []
               |),
-              M.get_name (| globals, "index" |)
+              M.get_name (| globals, locals_stack, "index" |)
             |), "to_le_bytes" |),
             make_list [],
             make_dict []
@@ -766,20 +776,20 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "mix_integers" ,
       M.call (|
-        M.get_name (| globals, "le_bytes_to_uint32_sequence" |),
+        M.get_name (| globals, locals_stack, "le_bytes_to_uint32_sequence" |),
         make_list [
-          M.get_name (| globals, "mix" |)
+          M.get_name (| globals, locals_stack, "mix" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "j" |),
+        M.get_name (| globals, locals_stack, "j" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "DATASET_PARENTS" |)
+        M.get_name (| globals, locals_stack, "DATASET_PARENTS" |)
       ],
       make_dict []
     |),
@@ -789,20 +799,20 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
             "cache_index" ,
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "fnv" |),
+                M.get_name (| globals, locals_stack, "fnv" |),
                 make_list [
                   BinOp.bit_xor (|
-                    M.get_name (| globals, "index" |),
-                    M.get_name (| globals, "j" |)
+                    M.get_name (| globals, locals_stack, "index" |),
+                    M.get_name (| globals, locals_stack, "j" |)
                   |);
-                  M.get_name (| globals, "mix_word" |)
+                  M.get_name (| globals, locals_stack, "mix_word" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_name (| globals, "cache" |)
+                  M.get_name (| globals, locals_stack, "cache" |)
                 ],
                 make_dict []
               |)
@@ -811,17 +821,17 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "parent" ,
             M.get_subscript (|
-              M.get_name (| globals, "cache" |),
-              M.get_name (| globals, "cache_index" |)
+              M.get_name (| globals, locals_stack, "cache" |),
+              M.get_name (| globals, locals_stack, "cache_index" |)
             |)
           |) in
           let _ := M.assign_local (|
             "mix_integers" ,
             M.call (|
-              M.get_name (| globals, "fnv_hash" |),
+              M.get_name (| globals, locals_stack, "fnv_hash" |),
               make_list [
-                M.get_name (| globals, "mix_integers" |);
-                M.get_name (| globals, "parent" |)
+                M.get_name (| globals, locals_stack, "mix_integers" |);
+                M.get_name (| globals, locals_stack, "parent" |)
               ],
               make_dict []
             |)
@@ -835,12 +845,12 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "mix" ,
       M.call (|
-        M.get_name (| globals, "Hash64" |),
+        M.get_name (| globals, locals_stack, "Hash64" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "le_uint32_sequence_to_bytes" |),
+            M.get_name (| globals, locals_stack, "le_uint32_sequence_to_bytes" |),
             make_list [
-              M.get_name (| globals, "mix_integers" |)
+              M.get_name (| globals, locals_stack, "mix_integers" |)
             ],
             make_dict []
           |)
@@ -850,9 +860,9 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak512" |),
+        M.get_name (| globals, locals_stack, "keccak512" |),
         make_list [
-          M.get_name (| globals, "mix" |)
+          M.get_name (| globals, locals_stack, "mix" |)
         ],
         make_dict []
       |)
@@ -860,8 +870,9 @@ Definition generate_dataset_item : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition generate_dataset : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate the full dataset for the block identified by `block_number`.
 
@@ -872,7 +883,7 @@ Definition generate_dataset : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "tuple" |),
+        M.get_name (| globals, locals_stack, "tuple" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: GeneratorExp *)"
         ],
@@ -882,8 +893,9 @@ Definition generate_dataset : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hashimoto : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header_hash"; "nonce"; "dataset_size"; "fetch_dataset_item" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header_hash"; "nonce"; "dataset_size"; "fetch_dataset_item" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the mix digest and the final value for a header, by aggregating
     data from the full dataset.
@@ -908,12 +920,12 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nonce_le" ,
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "reversed" |),
+            M.get_name (| globals, locals_stack, "reversed" |),
             make_list [
-              M.get_name (| globals, "nonce" |)
+              M.get_name (| globals, locals_stack, "nonce" |)
             ],
             make_dict []
           |)
@@ -924,11 +936,11 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "seed_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak512" |),
+        M.get_name (| globals, locals_stack, "keccak512" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "header_hash" |),
-            M.get_name (| globals, "nonce_le" |)
+            M.get_name (| globals, locals_stack, "header_hash" |),
+            M.get_name (| globals, locals_stack, "nonce_le" |)
           |)
         ],
         make_dict []
@@ -937,10 +949,10 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "seed_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U32" |), "from_le_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U32" |), "from_le_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "seed_hash" |),
+            M.get_name (| globals, locals_stack, "seed_hash" |),
             Constant.None_,
             Constant.int 4,
             Constant.None_
@@ -952,7 +964,7 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "rows" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "dataset_size" |),
+        M.get_name (| globals, locals_stack, "dataset_size" |),
         Constant.int 128
       |)
     |) in
@@ -960,25 +972,25 @@ Definition hashimoto : Value.t -> Value.t -> M :=
       "mix" ,
       BinOp.mult (|
         M.call (|
-          M.get_name (| globals, "le_bytes_to_uint32_sequence" |),
+          M.get_name (| globals, locals_stack, "le_bytes_to_uint32_sequence" |),
           make_list [
-            M.get_name (| globals, "seed_hash" |)
+            M.get_name (| globals, locals_stack, "seed_hash" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "MIX_BYTES" |),
-          M.get_name (| globals, "HASH_BYTES" |)
+          M.get_name (| globals, locals_stack, "MIX_BYTES" |),
+          M.get_name (| globals, locals_stack, "HASH_BYTES" |)
         |)
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "HASHIMOTO_ACCESSES" |)
+        M.get_name (| globals, locals_stack, "HASHIMOTO_ACCESSES" |)
       ],
       make_dict []
     |),
@@ -988,20 +1000,20 @@ Definition hashimoto : Value.t -> Value.t -> M :=
             "parent" ,
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "fnv" |),
+                M.get_name (| globals, locals_stack, "fnv" |),
                 make_list [
                   BinOp.bit_xor (|
-                    M.get_name (| globals, "i" |),
-                    M.get_name (| globals, "seed_head" |)
+                    M.get_name (| globals, locals_stack, "i" |),
+                    M.get_name (| globals, locals_stack, "seed_head" |)
                   |);
                   M.get_subscript (|
-                    M.get_name (| globals, "mix" |),
+                    M.get_name (| globals, locals_stack, "mix" |),
                     BinOp.mod_ (|
-                      M.get_name (| globals, "i" |),
+                      M.get_name (| globals, locals_stack, "i" |),
                       M.call (|
-                        M.get_name (| globals, "len" |),
+                        M.get_name (| globals, locals_stack, "len" |),
                         make_list [
-                          M.get_name (| globals, "mix" |)
+                          M.get_name (| globals, locals_stack, "mix" |)
                         ],
                         make_dict []
                       |)
@@ -1010,18 +1022,18 @@ Definition hashimoto : Value.t -> Value.t -> M :=
                 ],
                 make_dict []
               |),
-              M.get_name (| globals, "rows" |)
+              M.get_name (| globals, locals_stack, "rows" |)
             |)
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
-          M.get_name (| globals, "MIX_BYTES" |),
-          M.get_name (| globals, "HASH_BYTES" |)
+          M.get_name (| globals, locals_stack, "MIX_BYTES" |),
+          M.get_name (| globals, locals_stack, "HASH_BYTES" |)
         |)
       ],
       make_dict []
@@ -1031,20 +1043,20 @@ Definition hashimoto : Value.t -> Value.t -> M :=
                   BinOp.add,
                   "new_data",
                   M.call (|
-    M.get_name (| globals, "fetch_dataset_item" |),
+    M.get_name (| globals, locals_stack, "fetch_dataset_item" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 2,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "parent" |)
+              M.get_name (| globals, locals_stack, "parent" |)
             ],
             make_dict []
           |)
         |),
-        M.get_name (| globals, "j" |)
+        M.get_name (| globals, locals_stack, "j" |)
       |)
     ],
     make_dict []
@@ -1059,10 +1071,10 @@ Definition hashimoto : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "mix" ,
             M.call (|
-              M.get_name (| globals, "fnv_hash" |),
+              M.get_name (| globals, locals_stack, "fnv_hash" |),
               make_list [
-                M.get_name (| globals, "mix" |);
-                M.get_name (| globals, "new_data" |)
+                M.get_name (| globals, locals_stack, "mix" |);
+                M.get_name (| globals, locals_stack, "new_data" |)
               ],
               make_dict []
             |)
@@ -1079,15 +1091,15 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "mix" |)
+            M.get_name (| globals, locals_stack, "mix" |)
           ],
           make_dict []
         |);
@@ -1097,25 +1109,25 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compressed_mix" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compressed_mix" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "fnv" |),
+        M.get_name (| globals, locals_stack, "fnv" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "fnv" |),
+            M.get_name (| globals, locals_stack, "fnv" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "fnv" |),
+                M.get_name (| globals, locals_stack, "fnv" |),
                 make_list [
                   M.get_subscript (|
-                    M.get_name (| globals, "mix" |),
-                    M.get_name (| globals, "i" |)
+                    M.get_name (| globals, locals_stack, "mix" |),
+                    M.get_name (| globals, locals_stack, "i" |)
                   |);
                   M.get_subscript (|
-                    M.get_name (| globals, "mix" |),
+                    M.get_name (| globals, locals_stack, "mix" |),
                     BinOp.add (|
-                      M.get_name (| globals, "i" |),
+                      M.get_name (| globals, locals_stack, "i" |),
                       Constant.int 1
                     |)
                   |)
@@ -1123,9 +1135,9 @@ Definition hashimoto : Value.t -> Value.t -> M :=
                 make_dict []
               |);
               M.get_subscript (|
-                M.get_name (| globals, "mix" |),
+                M.get_name (| globals, locals_stack, "mix" |),
                 BinOp.add (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   Constant.int 2
                 |)
               |)
@@ -1133,9 +1145,9 @@ Definition hashimoto : Value.t -> Value.t -> M :=
             make_dict []
           |);
           M.get_subscript (|
-            M.get_name (| globals, "mix" |),
+            M.get_name (| globals, locals_stack, "mix" |),
             BinOp.add (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               Constant.int 3
             |)
           |)
@@ -1154,9 +1166,9 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "mix_digest" ,
       M.call (|
-        M.get_name (| globals, "le_uint32_sequence_to_bytes" |),
+        M.get_name (| globals, locals_stack, "le_uint32_sequence_to_bytes" |),
         make_list [
-          M.get_name (| globals, "compressed_mix" |)
+          M.get_name (| globals, locals_stack, "compressed_mix" |)
         ],
         make_dict []
       |)
@@ -1164,24 +1176,25 @@ Definition hashimoto : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "seed_hash" |),
-            M.get_name (| globals, "mix_digest" |)
+            M.get_name (| globals, locals_stack, "seed_hash" |),
+            M.get_name (| globals, locals_stack, "mix_digest" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition hashimoto_light : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header_hash"; "nonce"; "cache"; "dataset_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header_hash"; "nonce"; "cache"; "dataset_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Run the [`hashimoto`] algorithm by generating dataset item using the cache
     instead of loading the full dataset into main memory.
@@ -1207,12 +1220,12 @@ Definition hashimoto_light : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "hashimoto" |),
+        M.get_name (| globals, locals_stack, "hashimoto" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_name (| globals, "nonce" |);
-          M.get_name (| globals, "dataset_size" |);
-          M.get_name (| globals, "fetch_dataset_item" |)
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_name (| globals, locals_stack, "nonce" |);
+          M.get_name (| globals, locals_stack, "dataset_size" |);
+          M.get_name (| globals, locals_stack, "fetch_dataset_item" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/exceptions.v b/CoqOfPython/ethereum/exceptions.v
index 275bc32..4823691 100644
--- a/CoqOfPython/ethereum/exceptions.v
+++ b/CoqOfPython/ethereum/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.exceptions".
+Definition globals : Globals.t := "ethereum.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/fork_criteria.v b/CoqOfPython/ethereum/fork_criteria.v
index b4e814f..f4745fa 100644
--- a/CoqOfPython/ethereum/fork_criteria.v
+++ b/CoqOfPython/ethereum/fork_criteria.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.fork_criteria".
+Definition globals : Globals.t := "ethereum.fork_criteria".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,8 +40,9 @@ Definition ForkCriteria : Value.t :=
     [
       (
         "__eq__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "other" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "other" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Equality for fork criteria.
         " in
@@ -47,10 +50,10 @@ Definition ForkCriteria : Value.t :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "other" |);
-                  M.get_name (| globals, "ForkCriteria" |)
+                  M.get_name (| globals, locals_stack, "other" |);
+                  M.get_name (| globals, locals_stack, "ForkCriteria" |)
                 ],
                 make_dict []
               |),
@@ -58,8 +61,8 @@ Definition ForkCriteria : Value.t :=
             ltac:(M.monadic (
               let _ := M.return_ (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "self" |), "_internal" |),
-                  M.get_field (| M.get_name (| globals, "other" |), "_internal" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "other" |), "_internal" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -68,14 +71,15 @@ Definition ForkCriteria : Value.t :=
               M.pure Constant.None_
             )) |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "NotImplemented" |)
+            M.get_name (| globals, locals_stack, "NotImplemented" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__lt__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "other" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "other" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Ordering for fork criteria. Block number forks are before timestamp
         forks and scheduled forks are before unscheduled forks.
@@ -84,10 +88,10 @@ Definition ForkCriteria : Value.t :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "other" |);
-                  M.get_name (| globals, "ForkCriteria" |)
+                  M.get_name (| globals, locals_stack, "other" |);
+                  M.get_name (| globals, locals_stack, "ForkCriteria" |)
                 ],
                 make_dict []
               |),
@@ -95,8 +99,8 @@ Definition ForkCriteria : Value.t :=
             ltac:(M.monadic (
               let _ := M.return_ (|
                 Compare.lt (|
-                  M.get_field (| M.get_name (| globals, "self" |), "_internal" |),
-                  M.get_field (| M.get_name (| globals, "other" |), "_internal" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "other" |), "_internal" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -105,22 +109,23 @@ Definition ForkCriteria : Value.t :=
               M.pure Constant.None_
             )) |) in
           let _ := M.return_ (|
-            M.get_name (| globals, "NotImplemented" |)
+            M.get_name (| globals, locals_stack, "NotImplemented" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__hash__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         `ForkCriteria` is hashable, so it can be stored in dictionaries.
         " in
           let _ := M.return_ (|
             M.call (|
-              M.get_name (| globals, "hash" |),
+              M.get_name (| globals, locals_stack, "hash" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "self" |), "_internal" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |)
               ],
               make_dict []
             |)
@@ -138,37 +143,40 @@ Definition ByBlockNumber : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "block_number" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "block_number" ] in
+          ltac:(M.monadic (
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "_internal" |),
-            make_tuple [ M.get_field (| M.get_name (| globals, "ForkCriteria" |), "BLOCK_NUMBER" |); M.get_name (| globals, "block_number" |) ]
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |),
+            make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "ForkCriteria" |), "BLOCK_NUMBER" |); M.get_name (| globals, locals_stack, "block_number" |) ]
           |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "block_number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "block_number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "check",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "block_number"; "timestamp" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "block_number"; "timestamp" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Check whether the block number has been reached.
         " in
           let _ := M.return_ (|
             Compare.gt_e (|
-              M.get_name (| globals, "block_number" |),
-              M.get_field (| M.get_name (| globals, "self" |), "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "block_number" |)
             |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__repr__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         String representation of this object.
         " in
@@ -188,37 +196,40 @@ Definition ByTimestamp : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "timestamp" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "timestamp" ] in
+          ltac:(M.monadic (
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "_internal" |),
-            make_tuple [ M.get_field (| M.get_name (| globals, "ForkCriteria" |), "TIMESTAMP" |); M.get_name (| globals, "timestamp" |) ]
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |),
+            make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "ForkCriteria" |), "TIMESTAMP" |); M.get_name (| globals, locals_stack, "timestamp" |) ]
           |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "timestamp" |),
-            M.get_name (| globals, "timestamp" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "timestamp" |),
+            M.get_name (| globals, locals_stack, "timestamp" |)
           |) in
           M.pure Constant.None_))
       );
       (
         "check",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "block_number"; "timestamp" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "block_number"; "timestamp" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Check whether the timestamp has been reached.
         " in
           let _ := M.return_ (|
             Compare.gt_e (|
-              M.get_name (| globals, "timestamp" |),
-              M.get_field (| M.get_name (| globals, "self" |), "timestamp" |)
+              M.get_name (| globals, locals_stack, "timestamp" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "self" |), "timestamp" |)
             |)
           |) in
           M.pure Constant.None_))
       );
       (
         "__repr__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         String representation of this object.
         " in
@@ -238,18 +249,20 @@ Definition Unscheduled : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "_internal" |),
-            make_tuple [ M.get_field (| M.get_name (| globals, "ForkCriteria" |), "UNSCHEDULED" |); Constant.int 0 ]
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "_internal" |),
+            make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "ForkCriteria" |), "UNSCHEDULED" |); Constant.int 0 ]
           |) in
           M.pure Constant.None_))
       );
       (
         "check",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "block_number"; "timestamp" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "block_number"; "timestamp" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         Unscheduled forks never occur.
         " in
@@ -260,8 +273,9 @@ Definition Unscheduled : Value.t :=
       );
       (
         "__repr__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self" ] in
+          ltac:(M.monadic (
           let _ := Constant.str "
         String representation of this object.
         " in
diff --git a/CoqOfPython/ethereum/frontier/__init__.v b/CoqOfPython/ethereum/frontier/__init__.v
index e30d7e8..1608569 100644
--- a/CoqOfPython/ethereum/frontier/__init__.v
+++ b/CoqOfPython/ethereum/frontier/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.__init__".
+Definition globals : Globals.t := "ethereum.frontier.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -12,7 +14,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 0
     ],
diff --git a/CoqOfPython/ethereum/frontier/blocks.v b/CoqOfPython/ethereum/frontier/blocks.v
index 69e273c..e976a96 100644
--- a/CoqOfPython/ethereum/frontier/blocks.v
+++ b/CoqOfPython/ethereum/frontier/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.blocks".
+Definition globals : Globals.t := "ethereum.frontier.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/frontier/bloom.v b/CoqOfPython/ethereum/frontier/bloom.v
index c2d4fc3..9450670 100644
--- a/CoqOfPython/ethereum/frontier/bloom.v
+++ b/CoqOfPython/ethereum/frontier/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.bloom".
+Definition globals : Globals.t := "ethereum.frontier.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_frontier_fork_types_imports_Bloom :
   IsImported globals "ethereum.frontier.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/fork.v b/CoqOfPython/ethereum/frontier/fork.v
index ca8bfdb..2468924 100644
--- a/CoqOfPython/ethereum/frontier/fork.v
+++ b/CoqOfPython/ethereum/frontier/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.fork".
+Definition globals : Globals.t := "ethereum.frontier.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -129,7 +131,7 @@ Axiom ethereum_frontier_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 5,
@@ -153,7 +155,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -176,8 +178,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -197,13 +200,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -226,7 +230,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -237,9 +241,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -261,17 +265,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -284,13 +288,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -301,20 +305,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -339,110 +344,110 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -451,9 +456,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -462,9 +467,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -478,8 +483,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -498,95 +504,95 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -595,28 +601,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -642,26 +649,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -669,8 +676,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -688,9 +696,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -698,25 +706,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -725,41 +733,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -781,34 +790,35 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -832,13 +842,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -853,8 +863,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -895,50 +906,50 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |)
               ],
               make_dict []
             |)
@@ -946,18 +957,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -965,55 +976,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
+                M.get_name (| globals, locals_stack, "tx" |);
                 M.call (|
-                  M.get_name (| globals, "state_root" |),
+                  M.get_name (| globals, locals_stack, "state_root" |),
                   make_list [
-                    M.get_name (| globals, "state" |)
+                    M.get_name (| globals, locals_stack, "state" |)
                   ],
                   make_dict []
                 |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1022,56 +1033,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1082,8 +1093,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1108,27 +1120,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1137,9 +1149,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1157,46 +1169,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1207,19 +1219,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1228,23 +1240,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1252,16 +1264,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1275,13 +1287,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1296,11 +1308,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1308,88 +1320,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1402,8 +1414,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1432,44 +1445,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1481,19 +1494,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1506,8 +1519,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1535,30 +1549,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1566,98 +1580,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1665,10 +1679,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1676,20 +1690,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1698,10 +1712,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1709,41 +1723,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1751,35 +1765,35 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1790,13 +1804,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1825,17 +1840,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1850,8 +1865,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1880,14 +1896,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1895,7 +1911,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1903,7 +1919,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -1915,11 +1931,11 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "TX_BASE_COST" |),
-            M.get_name (| globals, "data_cost" |)
+            M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+            M.get_name (| globals, locals_stack, "data_cost" |)
           |)
         ],
         make_dict []
@@ -1928,8 +1944,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -1950,81 +1967,81 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           Constant.int 27
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 28
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "s" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "s" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "public_key" ,
       M.call (|
-        M.get_name (| globals, "secp256k1_recover" |),
+        M.get_name (| globals, locals_stack, "secp256k1_recover" |),
         make_list [
-          M.get_name (| globals, "r" |);
-          M.get_name (| globals, "s" |);
+          M.get_name (| globals, locals_stack, "r" |);
+          M.get_name (| globals, locals_stack, "s" |);
           BinOp.sub (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |);
           M.call (|
-            M.get_name (| globals, "signing_hash" |),
+            M.get_name (| globals, locals_stack, "signing_hash" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |)
@@ -2034,13 +2051,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2055,8 +2072,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in the signature.
 
@@ -2076,12 +2094,12 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2092,8 +2110,9 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2127,12 +2146,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2143,8 +2162,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2175,18 +2195,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2203,10 +2223,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2223,8 +2243,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2242,8 +2262,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and
     parent header.
@@ -2276,9 +2297,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_difficulty" |),
+        M.get_name (| globals, locals_stack, "parent_difficulty" |),
         M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 2048
           ],
@@ -2290,9 +2311,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "block_timestamp" |),
+          M.get_name (| globals, locals_stack, "block_timestamp" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_timestamp" |),
+            M.get_name (| globals, locals_stack, "parent_timestamp" |),
             Constant.int 13
           |)
         |),
@@ -2301,8 +2322,8 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "difficulty" ,
           BinOp.add (|
-            M.get_name (| globals, "parent_difficulty" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |) in
         M.pure Constant.None_
@@ -2311,8 +2332,8 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "difficulty" ,
           BinOp.sub (|
-            M.get_name (| globals, "parent_difficulty" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |) in
         M.pure Constant.None_
@@ -2322,9 +2343,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.sub (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |),
@@ -2337,7 +2358,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2347,7 +2368,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2357,10 +2378,10 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "difficulty" |);
-          M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+          M.get_name (| globals, locals_stack, "difficulty" |);
+          M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/fork_types.v b/CoqOfPython/ethereum/frontier/fork_types.v
index 1b8eb64..5da50e8 100644
--- a/CoqOfPython/ethereum/frontier/fork_types.v
+++ b/CoqOfPython/ethereum/frontier/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.fork_types".
+Definition globals : Globals.t := "ethereum.frontier.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/frontier/state.v b/CoqOfPython/ethereum/frontier/state.v
index 4e111a2..442525b 100644
--- a/CoqOfPython/ethereum/frontier/state.v
+++ b/CoqOfPython/ethereum/frontier/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.state".
+Definition globals : Globals.t := "ethereum.frontier.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,28 +710,29 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -724,36 +742,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -770,19 +790,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -798,21 +819,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -824,8 +845,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -839,19 +861,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -868,19 +891,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -895,11 +919,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/frontier/transactions.v b/CoqOfPython/ethereum/frontier/transactions.v
index 1c30efa..995a9a0 100644
--- a/CoqOfPython/ethereum/frontier/transactions.v
+++ b/CoqOfPython/ethereum/frontier/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.transactions".
+Definition globals : Globals.t := "ethereum.frontier.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/frontier/trie.v b/CoqOfPython/ethereum/frontier/trie.v
index f92e8c5..a8b7741 100644
--- a/CoqOfPython/ethereum/frontier/trie.v
+++ b/CoqOfPython/ethereum/frontier/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.trie".
+Definition globals : Globals.t := "ethereum.frontier.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -86,10 +88,10 @@ Axiom ethereum_frontier_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -102,14 +104,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -119,28 +121,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -178,14 +180,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -209,7 +212,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -225,10 +228,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -237,13 +240,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -252,10 +255,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -264,13 +267,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -279,10 +282,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -291,9 +294,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -301,7 +304,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -318,9 +321,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -330,9 +333,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -341,16 +344,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -360,8 +363,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -371,25 +375,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -401,10 +405,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -412,13 +416,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -433,23 +437,23 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "AssertionError" |),
+                  M.get_name (| globals, locals_stack, "AssertionError" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -474,8 +478,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -492,14 +497,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -510,8 +515,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -531,8 +537,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -540,14 +546,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -559,18 +565,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -590,10 +597,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -601,21 +608,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -628,11 +636,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -640,12 +648,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -653,7 +661,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -668,9 +676,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -678,8 +686,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -716,7 +725,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -727,9 +736,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -740,13 +749,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -754,15 +763,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -772,20 +781,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -803,7 +812,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -811,13 +820,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -826,15 +835,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -844,20 +853,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -875,9 +884,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -885,8 +894,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -903,14 +913,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -921,26 +931,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -948,17 +958,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -970,9 +980,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -980,8 +990,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1002,9 +1013,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1013,25 +1024,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1039,13 +1050,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1059,9 +1070,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1069,13 +1080,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1083,15 +1094,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1101,22 +1112,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1125,13 +1136,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1152,10 +1164,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1163,14 +1175,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1188,12 +1200,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1206,12 +1218,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1223,18 +1235,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1244,8 +1256,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1269,9 +1282,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1290,12 +1303,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1308,9 +1321,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1321,24 +1334,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1348,8 +1361,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1357,31 +1370,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1396,7 +1409,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1417,7 +1430,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1425,30 +1438,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1468,9 +1481,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1478,7 +1491,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1496,21 +1509,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1518,19 +1531,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1539,8 +1552,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1549,17 +1562,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1572,10 +1585,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/utils/__init__.v b/CoqOfPython/ethereum/frontier/utils/__init__.v
index 0506f75..bf74735 100644
--- a/CoqOfPython/ethereum/frontier/utils/__init__.v
+++ b/CoqOfPython/ethereum/frontier/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.utils.__init__".
+Definition globals : Globals.t := "ethereum.frontier.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/frontier/utils/address.v b/CoqOfPython/ethereum/frontier/utils/address.v
index 2fdbc8d..e45d41c 100644
--- a/CoqOfPython/ethereum/frontier/utils/address.v
+++ b/CoqOfPython/ethereum/frontier/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.utils.address".
+Definition globals : Globals.t := "ethereum.frontier.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,8 +40,9 @@ Axiom ethereum_frontier_fork_types_imports_Address :
   IsImported globals "ethereum.frontier.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -55,11 +58,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -74,8 +77,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -95,14 +99,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -114,7 +118,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -123,9 +127,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -133,9 +137,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/utils/hexadecimal.v b/CoqOfPython/ethereum/frontier/utils/hexadecimal.v
index 865d427..8a7d1dc 100644
--- a/CoqOfPython/ethereum/frontier/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/frontier/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.frontier.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_frontier_fork_types_imports_Root :
   IsImported globals "ethereum.frontier.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/frontier/utils/message.v b/CoqOfPython/ethereum/frontier/utils/message.v
index 6d47416..910cde2 100644
--- a/CoqOfPython/ethereum/frontier/utils/message.v
+++ b/CoqOfPython/ethereum/frontier/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.utils.message".
+Definition globals : Globals.t := "ethereum.frontier.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,8 +48,9 @@ Axiom ethereum_frontier_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.frontier.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -79,10 +82,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -91,20 +94,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -118,7 +121,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -127,7 +130,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -136,10 +139,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -147,19 +150,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -168,14 +171,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -186,7 +189,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -198,7 +201,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/vm/__init__.v b/CoqOfPython/ethereum/frontier/vm/__init__.v
index 2c943a9..c7dd433 100644
--- a/CoqOfPython/ethereum/frontier/vm/__init__.v
+++ b/CoqOfPython/ethereum/frontier/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.__init__".
+Definition globals : Globals.t := "ethereum.frontier.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,8 +90,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -102,31 +105,32 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -139,7 +143,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/exceptions.v b/CoqOfPython/ethereum/frontier/vm/exceptions.v
index f744f16..e226ebc 100644
--- a/CoqOfPython/ethereum/frontier/vm/exceptions.v
+++ b/CoqOfPython/ethereum/frontier/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.exceptions".
+Definition globals : Globals.t := "ethereum.frontier.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -69,22 +71,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/frontier/vm/gas.v b/CoqOfPython/ethereum/frontier/vm/gas.v
index 5e3fe66..43ac4d4 100644
--- a/CoqOfPython/ethereum/frontier/vm/gas.v
+++ b/CoqOfPython/ethereum/frontier/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.gas".
+Definition globals : Globals.t := "ethereum.frontier.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -54,7 +56,7 @@ Axiom ethereum_frontier_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -64,7 +66,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -74,7 +76,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -84,7 +86,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -94,7 +96,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -104,7 +106,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -114,7 +116,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -124,7 +126,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -134,7 +136,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -144,7 +146,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -154,7 +156,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -164,7 +166,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -174,7 +176,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -184,7 +186,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -194,7 +196,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -204,7 +206,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -214,7 +216,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -224,7 +226,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -234,7 +236,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -244,7 +246,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -254,7 +256,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -264,7 +266,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -274,7 +276,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -284,7 +286,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -294,7 +296,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -304,7 +306,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 40
     ],
@@ -314,7 +316,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -324,7 +326,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -334,7 +336,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -344,7 +346,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -354,7 +356,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -364,7 +366,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -374,7 +376,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -384,7 +386,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -394,7 +396,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -404,7 +406,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -414,7 +416,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -443,8 +445,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -457,13 +460,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -474,22 +477,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -499,8 +502,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -520,9 +524,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -532,15 +536,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -549,16 +553,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -577,7 +582,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -587,7 +592,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -597,12 +602,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -612,14 +617,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -633,9 +638,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -643,20 +648,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -669,8 +674,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -684,16 +689,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -701,9 +706,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -712,13 +717,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -728,10 +733,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -739,8 +744,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "gas"; "to"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "gas"; "to"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount for executing Opcodes `CALL` and `CALLCODE`.
 
@@ -764,17 +770,17 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "to" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "to" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -782,7 +788,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -790,13 +796,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -804,7 +810,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -812,12 +818,12 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "gas" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "gas" |)
           |),
-          M.get_name (| globals, "create_gas_cost" |)
+          M.get_name (| globals, locals_stack, "create_gas_cost" |)
         |),
-        M.get_name (| globals, "transfer_gas_cost" |)
+        M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -825,26 +831,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
-M.get_name (| globals, "gas" |)
+M.get_name (| globals, locals_stack, "gas" |)
       (* else *)
       )), ltac:(M.monadic (
 BinOp.add (|
-          M.get_name (| globals, "GAS_CALL_STIPEND" |),
-          M.get_name (| globals, "gas" |)
+          M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |)
       )) |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
-          M.get_name (| globals, "cost" |);
-          M.get_name (| globals, "stipend" |)
+          M.get_name (| globals, locals_stack, "cost" |);
+          M.get_name (| globals, locals_stack, "stipend" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/__init__.v b/CoqOfPython/ethereum/frontier/vm/instructions/__init__.v
index b95c8d5..543b21d 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/frontier/vm/instructions/arithmetic.v
index 542e2ad..e6bde37 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/bitwise.v b/CoqOfPython/ethereum/frontier/vm/instructions/bitwise.v
index f568271..88a91e5 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/block.v b/CoqOfPython/ethereum/frontier/vm/instructions/block.v
index cbcd26a..0439581 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/comparison.v b/CoqOfPython/ethereum/frontier/vm/instructions/comparison.v
index 8c59240..5b7be6f 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/control_flow.v b/CoqOfPython/ethereum/frontier/vm/instructions/control_flow.v
index ce039f3..4f1d4d7 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/environment.v b/CoqOfPython/ethereum/frontier/vm/instructions/environment.v
index 2ed9e35..c859e7a 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -60,8 +62,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -73,21 +76,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -96,14 +99,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -116,12 +120,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -130,42 +134,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -178,21 +183,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -201,14 +206,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -220,21 +226,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -243,14 +249,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -262,31 +269,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -300,30 +308,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -334,13 +342,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -349,14 +357,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -368,24 +377,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -397,14 +406,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -420,9 +430,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +440,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +450,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -451,12 +461,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -469,76 +479,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -550,24 +561,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -579,14 +590,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -602,9 +614,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -612,9 +624,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -622,9 +634,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -633,12 +645,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -651,76 +663,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -732,21 +745,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -755,14 +768,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -775,12 +789,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -789,26 +803,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -820,23 +834,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -849,12 +864,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -865,9 +880,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -875,9 +890,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -885,9 +900,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -896,12 +911,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -914,52 +929,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -967,27 +982,27 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/keccak.v b/CoqOfPython/ethereum/frontier/vm/instructions/keccak.v
index 393213b..58e84e0 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/log.v b/CoqOfPython/ethereum/frontier/vm/instructions/log.v
index f675d8d..937f587 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_frontier_vm_stack_imports_pop :
   IsImported globals "ethereum.frontier.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -66,9 +69,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -89,11 +92,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -102,9 +105,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -113,9 +116,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -128,74 +131,74 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -203,9 +206,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -213,9 +216,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -223,9 +226,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -233,9 +236,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/memory.v b/CoqOfPython/ethereum/frontier/vm/instructions/memory.v
index 56c03a2..e3aea6b 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/stack.v b/CoqOfPython/ethereum/frontier/vm/instructions/stack.v
index 18ec37d..2bd56d1 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_frontier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.frontier.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/storage.v b/CoqOfPython/ethereum/frontier/vm/instructions/storage.v
index 754b34a..1fd54fb 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,8 +44,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -58,9 +61,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -69,43 +72,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -119,9 +123,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -132,9 +136,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,11 +146,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -156,12 +160,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -170,14 +174,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -186,12 +190,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -200,8 +204,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -209,26 +213,26 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/instructions/system.v b/CoqOfPython/ethereum/frontier/vm/instructions/system.v
index 35a1fee..83f8c79 100644
--- a/CoqOfPython/ethereum/frontier/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/frontier/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.frontier.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -74,8 +76,9 @@ Axiom ethereum_frontier_vm_stack_imports_push :
   IsImported globals "ethereum.frontier.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -88,9 +91,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -98,9 +101,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -108,9 +111,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,35 +121,35 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -155,23 +158,23 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -179,14 +182,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -199,15 +202,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -223,10 +226,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -235,11 +238,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -250,8 +253,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -260,29 +263,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -297,27 +300,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -325,10 +328,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -336,23 +339,23 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -365,21 +368,21 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -394,14 +397,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -413,9 +417,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -423,9 +427,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -433,57 +437,58 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
@@ -493,24 +498,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -530,11 +535,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -542,10 +547,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -553,7 +558,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -561,10 +566,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -572,23 +577,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -601,19 +606,19 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -627,16 +632,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -648,14 +653,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -664,8 +669,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -677,12 +683,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -693,12 +699,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -709,9 +715,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -719,9 +725,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -729,9 +735,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -739,9 +745,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -749,9 +755,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -759,12 +765,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -773,42 +779,42 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -817,17 +823,17 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -838,25 +844,25 @@ Definition call : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -864,14 +870,15 @@ Definition call : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -883,12 +890,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -899,12 +906,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -915,9 +922,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -925,9 +932,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -935,9 +942,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -945,9 +952,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -955,26 +962,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -983,42 +990,42 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1027,17 +1034,17 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1048,25 +1055,25 @@ Definition callcode : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1074,14 +1081,15 @@ Definition callcode : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1093,12 +1101,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1108,37 +1116,37 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_ZERO" |)
+      M.get_name (| globals, locals_stack, "GAS_ZERO" |)
     |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1150,15 +1158,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1166,20 +1174,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1187,33 +1195,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1223,14 +1231,14 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
diff --git a/CoqOfPython/ethereum/frontier/vm/interpreter.v b/CoqOfPython/ethereum/frontier/vm/interpreter.v
index e1d892f..e3c5c81 100644
--- a/CoqOfPython/ethereum/frontier/vm/interpreter.v
+++ b/CoqOfPython/ethereum/frontier/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.interpreter".
+Definition globals : Globals.t := "ethereum.frontier.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,7 +111,7 @@ Axiom ethereum_frontier_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -128,8 +130,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -151,9 +154,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -165,10 +168,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -176,39 +179,39 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -222,10 +225,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -238,10 +241,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -251,14 +254,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -266,7 +269,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -278,44 +281,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -323,8 +326,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -341,27 +345,27 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -369,31 +373,31 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -401,22 +405,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -436,13 +441,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -454,17 +459,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -472,18 +477,18 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -495,10 +500,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -506,13 +511,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -520,22 +525,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -553,14 +559,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -568,13 +574,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/memory.v b/CoqOfPython/ethereum/frontier/vm/memory.v
index be21aab..b065d71 100644
--- a/CoqOfPython/ethereum/frontier/vm/memory.v
+++ b/CoqOfPython/ethereum/frontier/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.memory".
+Definition globals : Globals.t := "ethereum.frontier.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/__init__.v
index 34b3b7b..a61e39a 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ecrecover.v
index 6f8de26..5f49475 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_frontier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.frontier.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/identity.v
index ff7bb79..e032154 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_frontier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.frontier.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/mapping.v
index f2f606e..6aec646 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ripemd160.v
index 3f3bbd6..a49f853 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_frontier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.frontier.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/sha256.v
index e72a688..b7ef0c6 100644
--- a/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/frontier/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.frontier.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_frontier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.frontier.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/frontier/vm/runtime.v b/CoqOfPython/ethereum/frontier/vm/runtime.v
index 316e3e2..47407c6 100644
--- a/CoqOfPython/ethereum/frontier/vm/runtime.v
+++ b/CoqOfPython/ethereum/frontier/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.runtime".
+Definition globals : Globals.t := "ethereum.frontier.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_frontier_vm_instructions_imports_Ops :
   IsImported globals "ethereum.frontier.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/frontier/vm/stack.v b/CoqOfPython/ethereum/frontier/vm/stack.v
index 875e1e7..8345b56 100644
--- a/CoqOfPython/ethereum/frontier/vm/stack.v
+++ b/CoqOfPython/ethereum/frontier/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.frontier.vm.stack".
+Definition globals : Globals.t := "ethereum.frontier.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_frontier_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.frontier.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/genesis.v b/CoqOfPython/ethereum/genesis.v
index cd70564..522d754 100644
--- a/CoqOfPython/ethereum/genesis.v
+++ b/CoqOfPython/ethereum/genesis.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.genesis".
+Definition globals : Globals.t := "ethereum.genesis".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -62,7 +64,7 @@ Axiom ethereum_utils_hexadecimal_imports_hex_to_uint :
   IsImported globals "ethereum.utils.hexadecimal" "hex_to_uint".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition GenesisConfiguration : Value.t :=
@@ -76,8 +78,9 @@ Definition GenesisConfiguration : Value.t :=
     ].
 
 Definition get_genesis_configuration : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "genesis_file" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "genesis_file" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the genesis configuration from the given genesis json file.
 
@@ -98,11 +101,11 @@ Definition get_genesis_configuration : Value.t -> Value.t -> M :=
       "genesis_str_data" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "cast" |),
+          M.get_name (| globals, locals_stack, "cast" |),
           make_list [
-            M.get_name (| globals, "bytes" |);
+            M.get_name (| globals, locals_stack, "bytes" |);
             M.call (|
-              M.get_field (| M.get_name (| globals, "pkgutil" |), "get_data" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "pkgutil" |), "get_data" |),
               make_list [
                 Constant.str "ethereum";
                 Constant.str "(* At expr: unsupported node type: JoinedStr *)"
@@ -119,16 +122,16 @@ Definition get_genesis_configuration : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "genesis_data" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "json" |), "loads" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "json" |), "loads" |),
         make_list [
-          M.get_name (| globals, "genesis_str_data" |)
+          M.get_name (| globals, locals_stack, "genesis_str_data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "GenesisConfiguration" |),
+        M.get_name (| globals, locals_stack, "GenesisConfiguration" |),
         make_list [],
         make_dict []
       |)
@@ -136,8 +139,9 @@ Definition get_genesis_configuration : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_or_base_10_str_to_u256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "balance" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "balance" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The genesis format can have balances and timestamps as either base 10
     numbers or 0x prefixed hex. This function supports both.
@@ -146,7 +150,7 @@ Definition hex_or_base_10_str_to_u256 : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "balance" |), "startswith" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "balance" |), "startswith" |),
           make_list [
             Constant.str "0x"
           ],
@@ -156,9 +160,9 @@ Definition hex_or_base_10_str_to_u256 : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "hex_to_u256" |),
+            M.get_name (| globals, locals_stack, "hex_to_u256" |),
             make_list [
-              M.get_name (| globals, "balance" |)
+              M.get_name (| globals, locals_stack, "balance" |)
             ],
             make_dict []
           |)
@@ -168,12 +172,12 @@ Definition hex_or_base_10_str_to_u256 : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "balance" |)
+                  M.get_name (| globals, locals_stack, "balance" |)
                 ],
                 make_dict []
               |)
@@ -186,8 +190,9 @@ Definition hex_or_base_10_str_to_u256 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition add_genesis_block : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hardfork"; "chain"; "genesis" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hardfork"; "chain"; "genesis" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the genesis block to an empty blockchain.
 
@@ -234,9 +239,9 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
     " in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "account" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "account" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "genesis" |), "initial_accounts" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "genesis" |), "initial_accounts" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -244,29 +249,29 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "address" ,
             M.call (|
-              M.get_field (| M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "utils" |), "hexadecimal" |), "hex_to_address" |),
+              M.get_field (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "utils" |), "hexadecimal" |), "hex_to_address" |),
               make_list [
-                M.get_name (| globals, "address" |)
+                M.get_name (| globals, locals_stack, "address" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "state" |), "set_account" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "state" |), "set_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "chain" |), "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "fork_types" |), "Account" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "fork_types" |), "Account" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "account" |), "get" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "get" |),
                     make_list [
                       Constant.str "nonce";
                       Constant.str "0"
@@ -280,10 +285,10 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "hex_or_base_10_str_to_u256" |),
+            M.get_name (| globals, locals_stack, "hex_or_base_10_str_to_u256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "account" |), "get" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "get" |),
                 make_list [
                   Constant.str "balance";
                   Constant.int 0
@@ -294,10 +299,10 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "hex_to_bytes" |),
+            M.get_name (| globals, locals_stack, "hex_to_bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "account" |), "get" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "get" |),
                 make_list [
                   Constant.str "code";
                   Constant.str "0x"
@@ -315,10 +320,10 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
   |) in
           let _ :=
             M.for_ (|
-              make_tuple [ M.get_name (| globals, "key" |); M.get_name (| globals, "value" |) ],
+              make_tuple [ M.get_name (| globals, locals_stack, "key" |); M.get_name (| globals, locals_stack, "value" |) ],
               M.call (|
       M.get_field (| M.call (|
-        M.get_field (| M.get_name (| globals, "account" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "account" |), "get" |),
         make_list [
           Constant.str "storage";
           Constant.str "(* At expr: unsupported node type: Dict *)"
@@ -330,21 +335,21 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
     |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "state" |), "set_storage" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "state" |), "set_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "chain" |), "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "hex_to_bytes32" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes32" |),
         make_list [
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "hex_to_uint" |),
+        M.get_name (| globals, locals_stack, "hex_to_uint" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -371,9 +376,9 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "hasattr" |),
+          M.get_name (| globals, locals_stack, "hasattr" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "blocks" |), "Header" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "blocks" |), "Header" |);
             Constant.str "mix_digest"
           ],
           make_dict []
@@ -382,11 +387,11 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_name (| globals, "fields" |),
+            M.get_name (| globals, locals_stack, "fields" |),
             Constant.str "mix_digest"
           |),
           M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "fork_types" |), "Hash32" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "fork_types" |), "Hash32" |),
             make_list [
               BinOp.mult (|
                 Constant.bytes "00",
@@ -401,11 +406,11 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_name (| globals, "fields" |),
+            M.get_name (| globals, locals_stack, "fields" |),
             Constant.str "prev_randao"
           |),
           M.call (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "fork_types" |), "Hash32" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "fork_types" |), "Hash32" |),
             make_list [
               BinOp.mult (|
                 Constant.bytes "00",
@@ -421,9 +426,9 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "hasattr" |),
+          M.get_name (| globals, locals_stack, "hasattr" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "blocks" |), "Header" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "blocks" |), "Header" |);
             Constant.str "base_fee_per_gas"
           ],
           make_dict []
@@ -432,11 +437,11 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_name (| globals, "fields" |),
+            M.get_name (| globals, locals_stack, "fields" |),
             Constant.str "base_fee_per_gas"
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               BinOp.pow (|
                 Constant.int 10,
@@ -454,7 +459,7 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "genesis_header" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "blocks" |), "Header" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "blocks" |), "Header" |),
         make_list [],
         make_dict []
       |)
@@ -462,20 +467,20 @@ Definition add_genesis_block : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "genesis_block" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "hardfork" |), "blocks" |), "Block" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "hardfork" |), "blocks" |), "Block" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "genesis_block" |)
+      M.get_name (| globals, locals_stack, "genesis_block" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |),
-      M.get_field (| M.get_name (| globals, "genesis" |), "chain_id" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "genesis" |), "chain_id" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/__init__.v b/CoqOfPython/ethereum/gray_glacier/__init__.v
index 214f63d..81a302c 100644
--- a/CoqOfPython/ethereum/gray_glacier/__init__.v
+++ b/CoqOfPython/ethereum/gray_glacier/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.__init__".
+Definition globals : Globals.t := "ethereum.gray_glacier.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -13,7 +15,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 15050000
     ],
diff --git a/CoqOfPython/ethereum/gray_glacier/blocks.v b/CoqOfPython/ethereum/gray_glacier/blocks.v
index 04f7678..2713c4f 100644
--- a/CoqOfPython/ethereum/gray_glacier/blocks.v
+++ b/CoqOfPython/ethereum/gray_glacier/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.blocks".
+Definition globals : Globals.t := "ethereum.gray_glacier.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/gray_glacier/bloom.v b/CoqOfPython/ethereum/gray_glacier/bloom.v
index d2b450d..7e0e09e 100644
--- a/CoqOfPython/ethereum/gray_glacier/bloom.v
+++ b/CoqOfPython/ethereum/gray_glacier/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.bloom".
+Definition globals : Globals.t := "ethereum.gray_glacier.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_gray_glacier_fork_types_imports_Bloom :
   IsImported globals "ethereum.gray_glacier.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/fork.v b/CoqOfPython/ethereum/gray_glacier/fork.v
index 0bd20df..d29fe9d 100644
--- a/CoqOfPython/ethereum/gray_glacier/fork.v
+++ b/CoqOfPython/ethereum/gray_glacier/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.fork".
+Definition globals : Globals.t := "ethereum.gray_glacier.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -150,7 +152,7 @@ Axiom ethereum_gray_glacier_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -182,7 +184,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -200,10 +202,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -225,8 +227,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -246,13 +249,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -275,7 +279,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -286,9 +290,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -310,17 +314,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -333,13 +337,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -350,20 +354,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -388,112 +393,112 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -502,9 +507,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -513,9 +518,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -529,8 +534,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -553,22 +559,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -576,14 +582,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -592,40 +598,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -635,8 +641,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -645,36 +651,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -683,9 +689,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -693,8 +699,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -713,123 +720,123 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -838,28 +845,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -885,27 +893,27 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |);
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -913,8 +921,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -932,9 +941,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -942,25 +951,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -969,41 +978,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -1031,23 +1041,23 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1056,46 +1066,46 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -1104,38 +1114,39 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -1159,7 +1170,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -1168,10 +1179,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1181,9 +1192,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1196,10 +1207,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1209,9 +1220,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1221,7 +1232,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.return_ (|
-              M.get_name (| globals, "receipt" |)
+              M.get_name (| globals, locals_stack, "receipt" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -1240,8 +1251,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1286,22 +1298,22 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1310,16 +1322,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1327,9 +1339,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1337,14 +1349,14 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1352,18 +1364,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1371,49 +1383,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1422,56 +1434,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1482,8 +1494,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1508,27 +1521,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1537,9 +1550,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1557,46 +1570,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1607,19 +1620,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1628,23 +1641,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1652,16 +1665,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1675,13 +1688,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1696,11 +1709,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1708,88 +1721,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1802,8 +1815,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1832,44 +1846,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1881,19 +1895,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1906,8 +1920,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1935,30 +1950,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1967,10 +1982,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
@@ -1979,8 +1994,8 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1989,100 +2004,100 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "effective_gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "effective_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2090,7 +2105,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2099,10 +2114,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2110,25 +2125,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -2152,14 +2167,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2167,10 +2182,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2178,20 +2193,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -2200,17 +2215,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2218,41 +2233,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -2260,31 +2275,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -2295,20 +2310,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -2321,14 +2336,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2340,27 +2355,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2376,13 +2391,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -2411,17 +2427,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -2436,8 +2452,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2466,14 +2483,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2481,7 +2498,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2489,7 +2506,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2503,9 +2520,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2516,7 +2533,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2535,10 +2552,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2546,26 +2563,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2581,17 +2598,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2600,8 +2617,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2624,47 +2642,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2672,10 +2690,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2683,19 +2701,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2705,18 +2723,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2728,58 +2746,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2796,10 +2814,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2808,15 +2826,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2831,10 +2849,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2843,15 +2861,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2870,13 +2888,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2891,8 +2909,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2908,12 +2927,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2924,8 +2943,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2943,19 +2963,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2971,8 +2991,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2988,14 +3009,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3007,8 +3028,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -3024,14 +3046,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3043,8 +3065,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -3078,12 +3101,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -3094,8 +3117,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -3126,18 +3150,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3154,10 +3178,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3174,8 +3198,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -3193,8 +3217,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -3238,21 +3263,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -3262,11 +3287,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -3284,13 +3309,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -3299,13 +3324,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -3316,7 +3341,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -3326,7 +3351,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -3336,13 +3361,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/gray_glacier/fork_types.v b/CoqOfPython/ethereum/gray_glacier/fork_types.v
index b0a58e8..783edf8 100644
--- a/CoqOfPython/ethereum/gray_glacier/fork_types.v
+++ b/CoqOfPython/ethereum/gray_glacier/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.fork_types".
+Definition globals : Globals.t := "ethereum.gray_glacier.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/gray_glacier/state.v b/CoqOfPython/ethereum/gray_glacier/state.v
index 8cde655..a514f26 100644
--- a/CoqOfPython/ethereum/gray_glacier/state.v
+++ b/CoqOfPython/ethereum/gray_glacier/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.state".
+Definition globals : Globals.t := "ethereum.gray_glacier.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/transactions.v b/CoqOfPython/ethereum/gray_glacier/transactions.v
index 3fb1a1b..ac2e6ac 100644
--- a/CoqOfPython/ethereum/gray_glacier/transactions.v
+++ b/CoqOfPython/ethereum/gray_glacier/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.transactions".
+Definition globals : Globals.t := "ethereum.gray_glacier.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,14 +99,15 @@ Definition FeeMarketTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -112,17 +115,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -131,10 +134,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -144,9 +147,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -159,10 +162,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -172,9 +175,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -184,7 +187,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "Exception" |),
+                  M.get_name (| globals, locals_stack, "Exception" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -199,8 +202,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -208,10 +212,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -222,7 +226,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -231,11 +235,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -252,7 +256,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -261,11 +265,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -277,7 +281,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
-                let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                 M.pure Constant.None_
               )) |) in
             M.pure Constant.None_
@@ -286,7 +290,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/gray_glacier/trie.v b/CoqOfPython/ethereum/gray_glacier/trie.v
index 8b795d8..a3a2fcc 100644
--- a/CoqOfPython/ethereum/gray_glacier/trie.v
+++ b/CoqOfPython/ethereum/gray_glacier/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.trie".
+Definition globals : Globals.t := "ethereum.gray_glacier.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_gray_glacier_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,34 +124,34 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -187,14 +189,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -218,7 +221,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -234,10 +237,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -246,13 +249,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -261,10 +264,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -273,13 +276,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -288,10 +291,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -300,9 +303,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -310,7 +313,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -327,9 +330,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -339,9 +342,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -350,16 +353,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -369,8 +372,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -380,25 +384,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -410,10 +414,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -421,13 +425,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -442,27 +446,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -486,8 +490,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -504,14 +509,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -522,8 +527,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -543,8 +549,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -552,14 +558,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -571,18 +577,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -602,10 +609,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -613,21 +620,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -640,11 +648,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -652,12 +660,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -665,7 +673,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -680,9 +688,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -690,8 +698,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -728,7 +737,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -739,9 +748,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -752,13 +761,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -766,15 +775,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -784,20 +793,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -815,7 +824,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -823,13 +832,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -838,15 +847,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -856,20 +865,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -887,9 +896,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -897,8 +906,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -915,14 +925,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -933,26 +943,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -960,17 +970,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -982,9 +992,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -992,8 +1002,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1014,9 +1025,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1025,25 +1036,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1051,13 +1062,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1071,9 +1082,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1081,13 +1092,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1095,15 +1106,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1113,22 +1124,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1137,13 +1148,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1164,10 +1176,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1175,14 +1187,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1200,12 +1212,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1218,12 +1230,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1235,18 +1247,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1256,8 +1268,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1281,9 +1294,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1302,12 +1315,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1320,9 +1333,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1333,24 +1346,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1360,8 +1373,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1369,31 +1382,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1408,7 +1421,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1429,7 +1442,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1437,30 +1450,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1480,9 +1493,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1490,7 +1503,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1508,21 +1521,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1530,19 +1543,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1551,8 +1564,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1561,17 +1574,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1584,10 +1597,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/utils/__init__.v b/CoqOfPython/ethereum/gray_glacier/utils/__init__.v
index 180ce26..39b5ce6 100644
--- a/CoqOfPython/ethereum/gray_glacier/utils/__init__.v
+++ b/CoqOfPython/ethereum/gray_glacier/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.utils.__init__".
+Definition globals : Globals.t := "ethereum.gray_glacier.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/gray_glacier/utils/address.v b/CoqOfPython/ethereum/gray_glacier/utils/address.v
index a7dbc7d..4709a6e 100644
--- a/CoqOfPython/ethereum/gray_glacier/utils/address.v
+++ b/CoqOfPython/ethereum/gray_glacier/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.utils.address".
+Definition globals : Globals.t := "ethereum.gray_glacier.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_gray_glacier_fork_types_imports_Address :
   IsImported globals "ethereum.gray_glacier.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/utils/hexadecimal.v b/CoqOfPython/ethereum/gray_glacier/utils/hexadecimal.v
index 3ad2857..28d1537 100644
--- a/CoqOfPython/ethereum/gray_glacier/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/gray_glacier/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.gray_glacier.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_gray_glacier_fork_types_imports_Root :
   IsImported globals "ethereum.gray_glacier.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/gray_glacier/utils/message.v b/CoqOfPython/ethereum/gray_glacier/utils/message.v
index c2728e8..964fc28 100644
--- a/CoqOfPython/ethereum/gray_glacier/utils/message.v
+++ b/CoqOfPython/ethereum/gray_glacier/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.utils.message".
+Definition globals : Globals.t := "ethereum.gray_glacier.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_gray_glacier_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.gray_glacier.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/__init__.v b/CoqOfPython/ethereum/gray_glacier/vm/__init__.v
index 085ff3e..f29ae97 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/__init__.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.__init__".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/exceptions.v b/CoqOfPython/ethereum/gray_glacier/vm/exceptions.v
index 3eab002..9455938 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/exceptions.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.exceptions".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/gas.v b/CoqOfPython/ethereum/gray_glacier/vm/gas.v
index a6dcb12..c641090 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/gas.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.gas".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_gray_glacier_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -326,7 +328,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -336,7 +338,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -356,7 +358,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -376,7 +378,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -406,7 +408,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -416,7 +418,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -426,7 +428,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -465,8 +467,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -479,13 +482,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -496,22 +499,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -521,8 +524,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -542,9 +546,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -554,15 +558,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -571,16 +575,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,12 +624,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -634,14 +639,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -655,9 +660,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -665,20 +670,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -691,8 +696,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -706,16 +711,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -723,9 +728,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -734,13 +739,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -750,10 +755,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -761,8 +766,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -793,13 +799,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -807,32 +813,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -846,18 +852,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -868,15 +874,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -885,8 +891,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -902,9 +909,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/__init__.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/__init__.v
index a505398..aec2c0b 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/arithmetic.v
index d4d5eed..6362212 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/bitwise.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/bitwise.v
index c580c05..dc375db 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/block.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/block.v
index 1b25dc5..b511399 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/comparison.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/comparison.v
index 64165db..c003eff 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/control_flow.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/control_flow.v
index 0438b4c..5c7b1a5 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/environment.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/environment.v
index 13a017d..3bb0ad5 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,42 +1472,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1500,21 +1520,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1523,7 +1543,7 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/keccak.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/keccak.v
index a82edc7..ea84567 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/log.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/log.v
index 6e41a53..971c211 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_pop :
   IsImported globals "ethereum.gray_glacier.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/memory.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/memory.v
index 1516f1c..1f20979 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/stack.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/stack.v
index c680a10..5afb343 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_gray_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.gray_glacier.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/storage.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/storage.v
index 81cda0d..d897e28 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/instructions/system.v b/CoqOfPython/ethereum/gray_glacier/vm/instructions/system.v
index 0bd77ce..016e5bb 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,28 +107,29 @@ Axiom ethereum_gray_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.gray_glacier.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -136,32 +139,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -171,15 +174,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -195,10 +198,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -208,15 +211,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -237,29 +240,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -279,27 +282,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -307,10 +310,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -318,27 +321,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -351,25 +354,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -381,8 +384,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -394,9 +398,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -404,9 +408,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -414,9 +418,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -424,46 +428,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -472,26 +476,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -506,9 +511,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -516,9 +521,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -526,9 +531,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -537,9 +542,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -550,11 +555,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -564,12 +569,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -580,43 +585,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -625,26 +630,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -656,9 +662,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -666,9 +672,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -676,63 +682,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -740,24 +747,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -777,11 +784,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -789,10 +796,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -800,7 +807,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -808,10 +815,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -819,27 +826,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -852,23 +859,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -882,16 +889,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -903,14 +910,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -919,8 +926,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -932,12 +940,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -948,12 +956,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -964,9 +972,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -974,9 +982,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -984,9 +992,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -994,9 +1002,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1004,9 +1012,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1014,12 +1022,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1029,28 +1037,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1060,16 +1068,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1077,7 +1085,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1085,7 +1093,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1093,13 +1101,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1107,56 +1115,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1165,25 +1173,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1192,17 +1200,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1212,32 +1220,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1245,14 +1253,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1264,12 +1273,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1280,12 +1289,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1296,9 +1305,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,9 +1335,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1336,26 +1345,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1365,28 +1374,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1395,13 +1404,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1409,58 +1418,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1469,17 +1478,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1489,32 +1498,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1522,14 +1531,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1541,12 +1551,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1556,28 +1566,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1589,20 +1599,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1615,7 +1625,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1623,32 +1633,32 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1656,33 +1666,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1692,9 +1702,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1702,19 +1712,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1724,15 +1734,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1744,12 +1755,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1760,12 +1771,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1776,9 +1787,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1786,9 +1797,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1796,9 +1807,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1806,9 +1817,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1816,12 +1827,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1831,104 +1842,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1940,12 +1952,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1956,12 +1968,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1972,9 +1984,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1982,9 +1994,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1992,9 +2004,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2002,9 +2014,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2012,12 +2024,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2027,110 +2039,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2142,9 +2155,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2152,9 +2165,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2162,54 +2175,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/interpreter.v b/CoqOfPython/ethereum/gray_glacier/vm/interpreter.v
index af521c5..1aa54db 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/interpreter.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.interpreter".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -126,7 +128,7 @@ Axiom ethereum_gray_glacier_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -149,8 +151,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -172,9 +175,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -186,10 +189,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -197,44 +200,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -248,10 +251,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -264,10 +267,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -276,13 +279,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -292,12 +295,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -314,14 +317,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -329,7 +332,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -337,7 +340,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -349,22 +352,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -374,29 +377,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -404,8 +407,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -422,43 +426,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -466,24 +470,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -491,22 +495,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -526,13 +531,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -544,17 +549,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -562,10 +567,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -573,12 +578,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -590,10 +595,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -601,13 +606,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -615,22 +620,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -648,14 +654,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -663,13 +669,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/memory.v b/CoqOfPython/ethereum/gray_glacier/vm/memory.v
index 3aa8c8a..c3869cf 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/memory.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.memory".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/__init__.v
index fd5c1ed..6fbdf68 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/alt_bn128.v
index 35d4975..a2214fe 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_gray_glacier_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.gray_glacier.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/blake2f.v
index febbff6..c52e464 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_gray_glacier_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.gray_glacier.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ecrecover.v
index 2df1000..ed99d82 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_gray_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.gray_glacier.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/identity.v
index e41c6b5..52e89a2 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_gray_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.gray_glacier.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/mapping.v
index 61078a7..54b515b 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/modexp.v
index a12f219..49c54b1 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ripemd160.v
index 553c4c2..9e6da29 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_gray_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.gray_glacier.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/sha256.v
index ae4e91d..85a0889 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_gray_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.gray_glacier.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/runtime.v b/CoqOfPython/ethereum/gray_glacier/vm/runtime.v
index 4c10884..9bcce8b 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/runtime.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.runtime".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_gray_glacier_vm_instructions_imports_Ops :
   IsImported globals "ethereum.gray_glacier.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/gray_glacier/vm/stack.v b/CoqOfPython/ethereum/gray_glacier/vm/stack.v
index 4742c55..eb37711 100644
--- a/CoqOfPython/ethereum/gray_glacier/vm/stack.v
+++ b/CoqOfPython/ethereum/gray_glacier/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.gray_glacier.vm.stack".
+Definition globals : Globals.t := "ethereum.gray_glacier.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_gray_glacier_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.gray_glacier.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/__init__.v b/CoqOfPython/ethereum/homestead/__init__.v
index b8b69f5..362e5ec 100644
--- a/CoqOfPython/ethereum/homestead/__init__.v
+++ b/CoqOfPython/ethereum/homestead/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.__init__".
+Definition globals : Globals.t := "ethereum.homestead.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -15,7 +17,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 1150000
     ],
diff --git a/CoqOfPython/ethereum/homestead/blocks.v b/CoqOfPython/ethereum/homestead/blocks.v
index 237a920..a91ad83 100644
--- a/CoqOfPython/ethereum/homestead/blocks.v
+++ b/CoqOfPython/ethereum/homestead/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.blocks".
+Definition globals : Globals.t := "ethereum.homestead.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/homestead/bloom.v b/CoqOfPython/ethereum/homestead/bloom.v
index 04c7450..251dad4 100644
--- a/CoqOfPython/ethereum/homestead/bloom.v
+++ b/CoqOfPython/ethereum/homestead/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.bloom".
+Definition globals : Globals.t := "ethereum.homestead.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_homestead_fork_types_imports_Bloom :
   IsImported globals "ethereum.homestead.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/fork.v b/CoqOfPython/ethereum/homestead/fork.v
index 44f0c2f..d156e8e 100644
--- a/CoqOfPython/ethereum/homestead/fork.v
+++ b/CoqOfPython/ethereum/homestead/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.fork".
+Definition globals : Globals.t := "ethereum.homestead.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_homestead_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 5,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -181,8 +183,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -202,13 +205,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -231,7 +235,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -242,9 +246,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -266,17 +270,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -289,13 +293,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -306,20 +310,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -344,110 +349,110 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -456,9 +461,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -467,9 +472,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -483,8 +488,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -503,95 +509,95 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -600,28 +606,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -647,26 +654,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -674,8 +681,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -693,9 +701,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -703,25 +711,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -730,41 +738,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -786,34 +795,35 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -837,13 +847,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -858,8 +868,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -900,50 +911,50 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |)
               ],
               make_dict []
             |)
@@ -951,18 +962,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -970,55 +981,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
+                M.get_name (| globals, locals_stack, "tx" |);
                 M.call (|
-                  M.get_name (| globals, "state_root" |),
+                  M.get_name (| globals, locals_stack, "state_root" |),
                   make_list [
-                    M.get_name (| globals, "state" |)
+                    M.get_name (| globals, locals_stack, "state" |)
                   ],
                   make_dict []
                 |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1027,56 +1038,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1087,8 +1098,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1113,27 +1125,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1142,9 +1154,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1162,46 +1174,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1212,19 +1224,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1233,23 +1245,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1257,16 +1269,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1280,13 +1292,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1301,11 +1313,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1313,88 +1325,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1407,8 +1419,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1437,44 +1450,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1486,19 +1499,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1511,8 +1524,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1540,30 +1554,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1571,98 +1585,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1670,10 +1684,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1681,20 +1695,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1703,10 +1717,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1714,41 +1728,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1756,35 +1770,35 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1795,13 +1809,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1830,17 +1845,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1855,8 +1870,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1885,14 +1901,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1900,7 +1916,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1908,7 +1924,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -1922,9 +1938,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -1935,7 +1951,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1948,14 +1964,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -1964,8 +1980,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -1986,84 +2003,84 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           Constant.int 27
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 28
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "public_key" ,
       M.call (|
-        M.get_name (| globals, "secp256k1_recover" |),
+        M.get_name (| globals, locals_stack, "secp256k1_recover" |),
         make_list [
-          M.get_name (| globals, "r" |);
-          M.get_name (| globals, "s" |);
+          M.get_name (| globals, locals_stack, "r" |);
+          M.get_name (| globals, locals_stack, "s" |);
           BinOp.sub (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |);
           M.call (|
-            M.get_name (| globals, "signing_hash" |),
+            M.get_name (| globals, locals_stack, "signing_hash" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |)
@@ -2073,13 +2090,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2094,8 +2111,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in the signature.
 
@@ -2115,12 +2133,12 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2131,8 +2149,9 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2166,12 +2185,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2182,8 +2201,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2214,18 +2234,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2242,10 +2262,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2262,8 +2282,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2281,8 +2301,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2324,26 +2345,26 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
               Constant.int 1,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2361,13 +2382,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2375,9 +2396,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.sub (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |),
@@ -2390,7 +2411,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2400,7 +2421,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2410,13 +2431,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/homestead/fork_types.v b/CoqOfPython/ethereum/homestead/fork_types.v
index b6ac107..acb8202 100644
--- a/CoqOfPython/ethereum/homestead/fork_types.v
+++ b/CoqOfPython/ethereum/homestead/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.fork_types".
+Definition globals : Globals.t := "ethereum.homestead.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/homestead/state.v b/CoqOfPython/ethereum/homestead/state.v
index 139e07b..3fa3723 100644
--- a/CoqOfPython/ethereum/homestead/state.v
+++ b/CoqOfPython/ethereum/homestead/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.state".
+Definition globals : Globals.t := "ethereum.homestead.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,28 +710,29 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -724,36 +742,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -770,19 +790,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -798,21 +819,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -824,8 +845,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -839,19 +861,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -868,19 +891,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -895,11 +919,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/homestead/transactions.v b/CoqOfPython/ethereum/homestead/transactions.v
index 18720ce..c51a67c 100644
--- a/CoqOfPython/ethereum/homestead/transactions.v
+++ b/CoqOfPython/ethereum/homestead/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.transactions".
+Definition globals : Globals.t := "ethereum.homestead.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/homestead/trie.v b/CoqOfPython/ethereum/homestead/trie.v
index 62f57c9..60e2f90 100644
--- a/CoqOfPython/ethereum/homestead/trie.v
+++ b/CoqOfPython/ethereum/homestead/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.trie".
+Definition globals : Globals.t := "ethereum.homestead.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_homestead_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/utils/__init__.v b/CoqOfPython/ethereum/homestead/utils/__init__.v
index c70cb4e..3847a10 100644
--- a/CoqOfPython/ethereum/homestead/utils/__init__.v
+++ b/CoqOfPython/ethereum/homestead/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.utils.__init__".
+Definition globals : Globals.t := "ethereum.homestead.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/homestead/utils/address.v b/CoqOfPython/ethereum/homestead/utils/address.v
index 82ad5d5..9acdf08 100644
--- a/CoqOfPython/ethereum/homestead/utils/address.v
+++ b/CoqOfPython/ethereum/homestead/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.utils.address".
+Definition globals : Globals.t := "ethereum.homestead.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,8 +40,9 @@ Axiom ethereum_homestead_fork_types_imports_Address :
   IsImported globals "ethereum.homestead.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -55,11 +58,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -74,8 +77,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -95,14 +99,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -114,7 +118,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -123,9 +127,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -133,9 +137,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/utils/hexadecimal.v b/CoqOfPython/ethereum/homestead/utils/hexadecimal.v
index 83917ff..2b34614 100644
--- a/CoqOfPython/ethereum/homestead/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/homestead/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.homestead.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_homestead_fork_types_imports_Root :
   IsImported globals "ethereum.homestead.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/homestead/utils/message.v b/CoqOfPython/ethereum/homestead/utils/message.v
index 9f53490..08c3b9b 100644
--- a/CoqOfPython/ethereum/homestead/utils/message.v
+++ b/CoqOfPython/ethereum/homestead/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.utils.message".
+Definition globals : Globals.t := "ethereum.homestead.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,8 +48,9 @@ Axiom ethereum_homestead_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.homestead.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -81,10 +84,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -93,20 +96,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -120,7 +123,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -129,7 +132,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -138,10 +141,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -149,19 +152,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -170,14 +173,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -188,7 +191,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -200,7 +203,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/vm/__init__.v b/CoqOfPython/ethereum/homestead/vm/__init__.v
index 3653dc8..4199afd 100644
--- a/CoqOfPython/ethereum/homestead/vm/__init__.v
+++ b/CoqOfPython/ethereum/homestead/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.__init__".
+Definition globals : Globals.t := "ethereum.homestead.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,8 +90,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -102,31 +105,32 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -139,7 +143,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/exceptions.v b/CoqOfPython/ethereum/homestead/vm/exceptions.v
index 3c7fd2e..5a0a5b0 100644
--- a/CoqOfPython/ethereum/homestead/vm/exceptions.v
+++ b/CoqOfPython/ethereum/homestead/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.exceptions".
+Definition globals : Globals.t := "ethereum.homestead.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -69,22 +71,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/homestead/vm/gas.v b/CoqOfPython/ethereum/homestead/vm/gas.v
index db0a564..b99150c 100644
--- a/CoqOfPython/ethereum/homestead/vm/gas.v
+++ b/CoqOfPython/ethereum/homestead/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.gas".
+Definition globals : Globals.t := "ethereum.homestead.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -54,7 +56,7 @@ Axiom ethereum_homestead_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -64,7 +66,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -74,7 +76,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -84,7 +86,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -94,7 +96,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -104,7 +106,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -114,7 +116,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -124,7 +126,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -134,7 +136,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -144,7 +146,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -154,7 +156,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -164,7 +166,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -174,7 +176,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -184,7 +186,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -194,7 +196,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -204,7 +206,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -214,7 +216,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -224,7 +226,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -234,7 +236,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -244,7 +246,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -254,7 +256,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -264,7 +266,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -274,7 +276,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -284,7 +286,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -294,7 +296,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -304,7 +306,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 40
     ],
@@ -314,7 +316,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -324,7 +326,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -334,7 +336,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -344,7 +346,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -354,7 +356,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -364,7 +366,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -374,7 +376,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -384,7 +386,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -394,7 +396,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -404,7 +406,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -414,7 +416,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -443,8 +445,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -457,13 +460,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -474,22 +477,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -499,8 +502,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -520,9 +524,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -532,15 +536,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -549,16 +553,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -577,7 +582,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -587,7 +592,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -597,12 +602,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -612,14 +617,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -633,9 +638,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -643,20 +648,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -669,8 +674,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -684,16 +689,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -701,9 +706,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -712,13 +717,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -728,10 +733,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -739,8 +744,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "gas"; "to"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "gas"; "to"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount for executing Opcodes `CALL` and `CALLCODE`.
 
@@ -764,17 +770,17 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "to" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "to" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -782,7 +788,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -790,13 +796,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -804,7 +810,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -812,12 +818,12 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "gas" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "gas" |)
           |),
-          M.get_name (| globals, "create_gas_cost" |)
+          M.get_name (| globals, locals_stack, "create_gas_cost" |)
         |),
-        M.get_name (| globals, "transfer_gas_cost" |)
+        M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -825,26 +831,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
-M.get_name (| globals, "gas" |)
+M.get_name (| globals, locals_stack, "gas" |)
       (* else *)
       )), ltac:(M.monadic (
 BinOp.add (|
-          M.get_name (| globals, "GAS_CALL_STIPEND" |),
-          M.get_name (| globals, "gas" |)
+          M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |)
       )) |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
-          M.get_name (| globals, "cost" |);
-          M.get_name (| globals, "stipend" |)
+          M.get_name (| globals, locals_stack, "cost" |);
+          M.get_name (| globals, locals_stack, "stipend" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/__init__.v b/CoqOfPython/ethereum/homestead/vm/instructions/__init__.v
index 7a70aef..258a081 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/homestead/vm/instructions/arithmetic.v
index 1c889a2..ae67ed4 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/bitwise.v b/CoqOfPython/ethereum/homestead/vm/instructions/bitwise.v
index 9a886dd..9e98ba0 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/block.v b/CoqOfPython/ethereum/homestead/vm/instructions/block.v
index b5d16dd..b6515f4 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/comparison.v b/CoqOfPython/ethereum/homestead/vm/instructions/comparison.v
index dae8d81..927a6e9 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/control_flow.v b/CoqOfPython/ethereum/homestead/vm/instructions/control_flow.v
index 80e73c8..836cb75 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/environment.v b/CoqOfPython/ethereum/homestead/vm/instructions/environment.v
index d7f3281..54bf6fe 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -60,8 +62,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -73,21 +76,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -96,14 +99,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -116,12 +120,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -130,42 +134,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -178,21 +183,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -201,14 +206,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -220,21 +226,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -243,14 +249,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -262,31 +269,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -300,30 +308,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -334,13 +342,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -349,14 +357,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -368,24 +377,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -397,14 +406,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -420,9 +430,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +440,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +450,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -451,12 +461,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -469,76 +479,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -550,24 +561,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -579,14 +590,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -602,9 +614,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -612,9 +624,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -622,9 +634,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -633,12 +645,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -651,76 +663,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -732,21 +745,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -755,14 +768,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -775,12 +789,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -789,26 +803,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -820,23 +834,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -849,12 +864,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -865,9 +880,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -875,9 +890,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -885,9 +900,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -896,12 +911,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -914,52 +929,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -967,27 +982,27 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/keccak.v b/CoqOfPython/ethereum/homestead/vm/instructions/keccak.v
index 6e22190..635558c 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/log.v b/CoqOfPython/ethereum/homestead/vm/instructions/log.v
index 7780f07..aed85db 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_homestead_vm_stack_imports_pop :
   IsImported globals "ethereum.homestead.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -66,9 +69,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -89,11 +92,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -102,9 +105,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -113,9 +116,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -128,74 +131,74 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -203,9 +206,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -213,9 +216,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -223,9 +226,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -233,9 +236,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/memory.v b/CoqOfPython/ethereum/homestead/vm/instructions/memory.v
index e8029f0..7724229 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/stack.v b/CoqOfPython/ethereum/homestead/vm/instructions/stack.v
index dbfa9fb..59c7c5f 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_homestead_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.homestead.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/storage.v b/CoqOfPython/ethereum/homestead/vm/instructions/storage.v
index aa3f335..28827a1 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,8 +44,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -58,9 +61,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -69,43 +72,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -119,9 +123,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -132,9 +136,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,11 +146,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -156,12 +160,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -170,14 +174,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -186,12 +190,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -200,8 +204,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -209,26 +213,26 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/instructions/system.v b/CoqOfPython/ethereum/homestead/vm/instructions/system.v
index 924bdf2..6bf54d2 100644
--- a/CoqOfPython/ethereum/homestead/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/homestead/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.homestead.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_homestead_vm_stack_imports_push :
   IsImported globals "ethereum.homestead.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -90,9 +93,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -100,9 +103,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -110,9 +113,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,35 +123,35 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -157,23 +160,23 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -181,14 +184,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -201,15 +204,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -225,10 +228,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -237,11 +240,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -252,8 +255,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -262,29 +265,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -299,27 +302,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -327,10 +330,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -338,23 +341,23 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -367,21 +370,21 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -396,14 +399,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -415,9 +419,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -425,9 +429,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -435,57 +439,58 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
@@ -495,24 +500,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -532,11 +537,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -544,10 +549,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -555,7 +560,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -563,10 +568,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -574,23 +579,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -603,19 +608,19 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -629,16 +634,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -650,14 +655,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -666,8 +671,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -679,12 +685,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -695,12 +701,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -711,9 +717,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -721,9 +727,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -731,9 +737,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -741,9 +747,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -751,9 +757,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -761,12 +767,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -775,42 +781,42 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -819,17 +825,17 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -840,26 +846,26 @@ Definition call : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -867,14 +873,15 @@ Definition call : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -886,12 +893,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -902,12 +909,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -918,9 +925,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -928,9 +935,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -938,9 +945,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -948,9 +955,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -958,26 +965,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -986,42 +993,42 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "to" |);
-          M.get_name (| globals, "value" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "to" |);
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1030,17 +1037,17 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1051,26 +1058,26 @@ Definition callcode : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1078,14 +1085,15 @@ Definition callcode : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1097,12 +1105,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1112,37 +1120,37 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_ZERO" |)
+      M.get_name (| globals, locals_stack, "GAS_ZERO" |)
     |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1154,15 +1162,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1170,20 +1178,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1191,33 +1199,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1227,22 +1235,23 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1254,12 +1263,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1270,12 +1279,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1286,9 +1295,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1296,9 +1305,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,59 +1335,59 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CALL" |),
-          M.get_name (| globals, "gas" |)
+          M.get_name (| globals, locals_stack, "GAS_CALL" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/interpreter.v b/CoqOfPython/ethereum/homestead/vm/interpreter.v
index e60282d..9f1e4f6 100644
--- a/CoqOfPython/ethereum/homestead/vm/interpreter.v
+++ b/CoqOfPython/ethereum/homestead/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.interpreter".
+Definition globals : Globals.t := "ethereum.homestead.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,7 +111,7 @@ Axiom ethereum_homestead_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -128,8 +130,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -151,9 +154,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -165,10 +168,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -176,39 +179,39 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -222,10 +225,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -238,10 +241,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -251,14 +254,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -266,7 +269,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -278,44 +281,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -323,8 +326,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -341,27 +345,27 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -369,24 +373,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -394,22 +398,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -429,13 +434,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -447,17 +452,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -465,10 +470,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -476,12 +481,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -493,10 +498,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -504,13 +509,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -518,22 +523,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -551,14 +557,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -566,13 +572,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/memory.v b/CoqOfPython/ethereum/homestead/vm/memory.v
index e10df21..a6a5e4e 100644
--- a/CoqOfPython/ethereum/homestead/vm/memory.v
+++ b/CoqOfPython/ethereum/homestead/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.memory".
+Definition globals : Globals.t := "ethereum.homestead.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/__init__.v
index f7f7382..97692d3 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ecrecover.v
index e4781ca..d702154 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_homestead_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.homestead.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/identity.v
index 1f02089..afb4248 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_homestead_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.homestead.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/mapping.v
index 317a774..ce1afde 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ripemd160.v
index 659b238..051f03f 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_homestead_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.homestead.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/sha256.v
index e8dbb14..992b73b 100644
--- a/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/homestead/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.homestead.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_homestead_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.homestead.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/homestead/vm/runtime.v b/CoqOfPython/ethereum/homestead/vm/runtime.v
index d8d8829..fc59d58 100644
--- a/CoqOfPython/ethereum/homestead/vm/runtime.v
+++ b/CoqOfPython/ethereum/homestead/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.runtime".
+Definition globals : Globals.t := "ethereum.homestead.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_homestead_vm_instructions_imports_Ops :
   IsImported globals "ethereum.homestead.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/homestead/vm/stack.v b/CoqOfPython/ethereum/homestead/vm/stack.v
index e8c3493..d6366fc 100644
--- a/CoqOfPython/ethereum/homestead/vm/stack.v
+++ b/CoqOfPython/ethereum/homestead/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.homestead.vm.stack".
+Definition globals : Globals.t := "ethereum.homestead.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_homestead_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.homestead.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/__init__.v b/CoqOfPython/ethereum/istanbul/__init__.v
index 41dba6f..45c02fa 100644
--- a/CoqOfPython/ethereum/istanbul/__init__.v
+++ b/CoqOfPython/ethereum/istanbul/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.__init__".
+Definition globals : Globals.t := "ethereum.istanbul.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 9069000
     ],
diff --git a/CoqOfPython/ethereum/istanbul/blocks.v b/CoqOfPython/ethereum/istanbul/blocks.v
index 09c7599..50a1dcb 100644
--- a/CoqOfPython/ethereum/istanbul/blocks.v
+++ b/CoqOfPython/ethereum/istanbul/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.blocks".
+Definition globals : Globals.t := "ethereum.istanbul.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/istanbul/bloom.v b/CoqOfPython/ethereum/istanbul/bloom.v
index 9f67f06..0093baa 100644
--- a/CoqOfPython/ethereum/istanbul/bloom.v
+++ b/CoqOfPython/ethereum/istanbul/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.bloom".
+Definition globals : Globals.t := "ethereum.istanbul.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_istanbul_fork_types_imports_Bloom :
   IsImported globals "ethereum.istanbul.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/fork.v b/CoqOfPython/ethereum/istanbul/fork.v
index ce58ae7..3090be9 100644
--- a/CoqOfPython/ethereum/istanbul/fork.v
+++ b/CoqOfPython/ethereum/istanbul/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.fork".
+Definition globals : Globals.t := "ethereum.istanbul.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_istanbul_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -176,10 +178,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -201,8 +203,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -222,13 +225,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -251,7 +255,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -262,9 +266,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -286,17 +290,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -309,13 +313,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -326,20 +330,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -364,111 +369,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -477,9 +482,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -488,9 +493,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -504,8 +509,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -526,101 +532,101 @@ Definition validate_header : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -629,28 +635,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -676,26 +683,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -703,8 +710,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -722,9 +730,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -732,25 +740,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -759,41 +767,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -817,35 +826,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -869,13 +879,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -890,8 +900,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -934,51 +945,51 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -986,18 +997,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1005,49 +1016,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1056,56 +1067,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1116,8 +1127,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1142,27 +1154,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1171,9 +1183,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1191,46 +1203,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1241,19 +1253,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1262,23 +1274,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1286,16 +1298,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1309,13 +1321,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1330,11 +1342,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1342,88 +1354,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1436,8 +1448,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1466,44 +1479,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1515,19 +1528,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1540,8 +1553,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1569,30 +1583,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1600,98 +1614,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1699,10 +1713,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1710,20 +1724,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1732,10 +1746,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1743,41 +1757,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1785,31 +1799,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1820,20 +1834,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1846,14 +1860,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1865,27 +1879,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1901,13 +1915,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1936,17 +1951,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1961,8 +1976,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1991,14 +2007,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2006,7 +2022,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2014,7 +2030,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2028,9 +2044,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2041,7 +2057,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2054,14 +2070,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2070,8 +2086,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2094,47 +2111,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2143,12 +2160,12 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -2158,18 +2175,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_pre155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |)
+                  M.get_name (| globals, locals_stack, "tx" |)
                 ],
                 make_dict []
               |)
@@ -2181,58 +2198,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 35
                 |),
                 BinOp.mult (|
-                  M.get_name (| globals, "chain_id" |),
+                  M.get_name (| globals, locals_stack, "chain_id" |),
                   Constant.int 2
                 |)
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |);
-                  M.get_name (| globals, "chain_id" |)
+                  M.get_name (| globals, locals_stack, "tx" |);
+                  M.get_name (| globals, locals_stack, "chain_id" |)
                 ],
                 make_dict []
               |)
@@ -2244,13 +2261,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2265,8 +2282,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2282,12 +2300,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2298,8 +2316,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2317,19 +2336,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2345,8 +2364,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2380,12 +2400,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2396,8 +2416,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2428,18 +2449,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2456,10 +2477,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2476,8 +2497,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2495,8 +2516,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2540,21 +2562,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -2564,11 +2586,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2586,13 +2608,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2601,13 +2623,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -2618,7 +2640,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2628,7 +2650,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2638,13 +2660,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/istanbul/fork_types.v b/CoqOfPython/ethereum/istanbul/fork_types.v
index f19cd79..c223ec3 100644
--- a/CoqOfPython/ethereum/istanbul/fork_types.v
+++ b/CoqOfPython/ethereum/istanbul/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.fork_types".
+Definition globals : Globals.t := "ethereum.istanbul.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/istanbul/state.v b/CoqOfPython/ethereum/istanbul/state.v
index d2aaed7..1cdbfcb 100644
--- a/CoqOfPython/ethereum/istanbul/state.v
+++ b/CoqOfPython/ethereum/istanbul/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.state".
+Definition globals : Globals.t := "ethereum.istanbul.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/transactions.v b/CoqOfPython/ethereum/istanbul/transactions.v
index 0658f47..b3f8e81 100644
--- a/CoqOfPython/ethereum/istanbul/transactions.v
+++ b/CoqOfPython/ethereum/istanbul/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.transactions".
+Definition globals : Globals.t := "ethereum.istanbul.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/istanbul/trie.v b/CoqOfPython/ethereum/istanbul/trie.v
index 0265390..9a208c8 100644
--- a/CoqOfPython/ethereum/istanbul/trie.v
+++ b/CoqOfPython/ethereum/istanbul/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.trie".
+Definition globals : Globals.t := "ethereum.istanbul.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_istanbul_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/utils/__init__.v b/CoqOfPython/ethereum/istanbul/utils/__init__.v
index bcee1bf..6587917 100644
--- a/CoqOfPython/ethereum/istanbul/utils/__init__.v
+++ b/CoqOfPython/ethereum/istanbul/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.utils.__init__".
+Definition globals : Globals.t := "ethereum.istanbul.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/istanbul/utils/address.v b/CoqOfPython/ethereum/istanbul/utils/address.v
index 340714a..6d4b32f 100644
--- a/CoqOfPython/ethereum/istanbul/utils/address.v
+++ b/CoqOfPython/ethereum/istanbul/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.utils.address".
+Definition globals : Globals.t := "ethereum.istanbul.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_istanbul_fork_types_imports_Address :
   IsImported globals "ethereum.istanbul.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/utils/hexadecimal.v b/CoqOfPython/ethereum/istanbul/utils/hexadecimal.v
index 0486e96..326dbeb 100644
--- a/CoqOfPython/ethereum/istanbul/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/istanbul/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.istanbul.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_istanbul_fork_types_imports_Root :
   IsImported globals "ethereum.istanbul.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/istanbul/utils/message.v b/CoqOfPython/ethereum/istanbul/utils/message.v
index 2ff4fec..764c0cc 100644
--- a/CoqOfPython/ethereum/istanbul/utils/message.v
+++ b/CoqOfPython/ethereum/istanbul/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.utils.message".
+Definition globals : Globals.t := "ethereum.istanbul.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_istanbul_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.istanbul.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -85,10 +88,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -97,20 +100,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -124,7 +127,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -133,7 +136,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -142,10 +145,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -153,19 +156,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -174,14 +177,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -192,7 +195,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -204,7 +207,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/__init__.v b/CoqOfPython/ethereum/istanbul/vm/__init__.v
index dc4ef8a..130d65d 100644
--- a/CoqOfPython/ethereum/istanbul/vm/__init__.v
+++ b/CoqOfPython/ethereum/istanbul/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.__init__".
+Definition globals : Globals.t := "ethereum.istanbul.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -95,8 +97,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -109,30 +112,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -140,19 +143,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,8 +167,9 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -180,15 +184,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -201,8 +205,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -210,19 +214,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -238,7 +242,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/exceptions.v b/CoqOfPython/ethereum/istanbul/vm/exceptions.v
index 3ba8068..60bd736 100644
--- a/CoqOfPython/ethereum/istanbul/vm/exceptions.v
+++ b/CoqOfPython/ethereum/istanbul/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.exceptions".
+Definition globals : Globals.t := "ethereum.istanbul.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/istanbul/vm/gas.v b/CoqOfPython/ethereum/istanbul/vm/gas.v
index b2000e8..ec6291f 100644
--- a/CoqOfPython/ethereum/istanbul/vm/gas.v
+++ b/CoqOfPython/ethereum/istanbul/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.gas".
+Definition globals : Globals.t := "ethereum.istanbul.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_istanbul_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 800
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -436,7 +438,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -446,7 +448,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -456,7 +458,7 @@ Definition GAS_CODE_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -466,7 +468,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -495,8 +497,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -509,13 +512,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -526,22 +529,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -551,8 +554,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -572,9 +576,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -584,15 +588,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -601,16 +605,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -629,7 +634,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -639,7 +644,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -649,12 +654,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -664,14 +669,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -685,9 +690,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -695,20 +700,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -721,8 +726,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -736,16 +741,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -753,9 +758,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -764,13 +769,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -780,10 +785,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -791,8 +796,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -823,13 +829,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -837,32 +843,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -876,18 +882,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -898,15 +904,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -915,8 +921,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -932,9 +939,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/__init__.v b/CoqOfPython/ethereum/istanbul/vm/instructions/__init__.v
index 645b22b..ac4aa10 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/istanbul/vm/instructions/arithmetic.v
index 6c1634f..24ded16 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/bitwise.v b/CoqOfPython/ethereum/istanbul/vm/instructions/bitwise.v
index cf2b256..9d39653 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/block.v b/CoqOfPython/ethereum/istanbul/vm/instructions/block.v
index 9b0f81f..73b1cf4 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/comparison.v b/CoqOfPython/ethereum/istanbul/vm/instructions/comparison.v
index 3ddb9b3..9841d35 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/control_flow.v b/CoqOfPython/ethereum/istanbul/vm/instructions/control_flow.v
index 540d4de..dc7875f 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/environment.v b/CoqOfPython/ethereum/istanbul/vm/instructions/environment.v
index 6cda0d2..6d95393 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -78,8 +80,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -91,21 +94,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -114,14 +117,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -134,12 +138,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -148,42 +152,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -196,21 +201,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -219,14 +224,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -238,21 +244,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -261,14 +267,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -280,31 +287,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -318,30 +326,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -352,13 +360,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -367,14 +375,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -386,24 +395,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -415,14 +424,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -438,9 +448,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -448,9 +458,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -458,9 +468,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -469,12 +479,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -487,76 +497,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -568,24 +579,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -597,14 +608,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -620,9 +632,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -630,9 +642,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -640,9 +652,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -651,12 +663,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -669,76 +681,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -750,21 +763,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -773,14 +786,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -793,12 +807,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -807,26 +821,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -838,23 +852,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -867,12 +882,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -883,9 +898,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -893,9 +908,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -903,9 +918,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -914,12 +929,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -932,52 +947,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -985,34 +1000,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1023,24 +1039,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1052,14 +1068,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1071,9 +1088,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1081,9 +1098,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1091,9 +1108,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1102,12 +1119,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1120,108 +1137,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1232,12 +1250,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1246,20 +1264,20 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_CODE_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_CODE_HASH" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1268,15 +1286,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1289,12 +1307,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1305,23 +1323,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1333,35 +1352,35 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/keccak.v b/CoqOfPython/ethereum/istanbul/vm/instructions/keccak.v
index e4fa0c2..f4f52cd 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/log.v b/CoqOfPython/ethereum/istanbul/vm/instructions/log.v
index 8471fb8..aa83110 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_istanbul_vm_stack_imports_pop :
   IsImported globals "ethereum.istanbul.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/memory.v b/CoqOfPython/ethereum/istanbul/vm/instructions/memory.v
index 139811a..813908d 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/stack.v b/CoqOfPython/ethereum/istanbul/vm/instructions/stack.v
index 36a6974..f654b54 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_istanbul_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.istanbul.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/storage.v b/CoqOfPython/ethereum/istanbul/vm/instructions/storage.v
index e5e7cdf..19cb686 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -54,8 +56,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -70,9 +73,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -81,43 +84,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -131,9 +135,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -144,32 +148,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -177,11 +181,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -191,13 +195,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -207,21 +211,21 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_cost" ,
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_cost" ,
-              M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -230,7 +234,7 @@ Definition sstore : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -238,8 +242,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -248,18 +252,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -270,11 +274,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -289,12 +293,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -303,11 +307,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -321,8 +325,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -330,20 +334,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_SLOAD" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
       |)
     ],
     make_dict []
@@ -354,13 +358,13 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-        M.get_name (| globals, "GAS_SLOAD" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+        M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
       |)
     ],
     make_dict []
@@ -379,34 +383,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/instructions/system.v b/CoqOfPython/ethereum/istanbul/vm/instructions/system.v
index 04f4e5a..c384f87 100644
--- a/CoqOfPython/ethereum/istanbul/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/istanbul/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.istanbul.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,8 +107,9 @@ Axiom ethereum_istanbul_vm_stack_imports_push :
   IsImported globals "ethereum.istanbul.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
@@ -114,12 +117,12 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -129,32 +132,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -164,15 +167,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -188,10 +191,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -201,15 +204,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -230,29 +233,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -272,27 +275,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -300,10 +303,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -311,27 +314,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -344,25 +347,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -374,8 +377,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -387,9 +391,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,9 +401,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -407,9 +411,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -417,46 +421,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -465,26 +469,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -499,9 +504,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -509,9 +514,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -519,9 +524,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -530,9 +535,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -543,11 +548,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -557,12 +562,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -573,43 +578,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -618,26 +623,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -649,9 +655,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -659,9 +665,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -669,63 +675,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -733,24 +740,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -770,11 +777,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -782,10 +789,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -793,7 +800,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -801,10 +808,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -812,27 +819,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -845,23 +852,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -875,16 +882,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -896,14 +903,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -912,8 +919,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -925,12 +933,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -941,12 +949,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -957,9 +965,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -967,9 +975,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -977,9 +985,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -987,9 +995,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -997,9 +1005,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1007,12 +1015,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1024,15 +1032,15 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             M.call (|
-              M.get_name (| globals, "is_account_alive" |),
+              M.get_name (| globals, locals_stack, "is_account_alive" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "to" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "to" |)
               ],
               make_dict []
             |)
@@ -1041,7 +1049,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1049,7 +1057,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1057,13 +1065,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1071,56 +1079,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1129,25 +1137,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1156,17 +1164,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1176,32 +1184,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1209,14 +1217,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1228,12 +1237,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1244,12 +1253,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1260,9 +1269,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1270,9 +1279,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1280,9 +1289,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1290,9 +1299,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1300,26 +1309,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1330,13 +1339,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1344,58 +1353,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1404,17 +1413,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1424,32 +1433,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1457,14 +1466,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1476,12 +1486,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1491,27 +1501,27 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1524,7 +1534,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1533,33 +1543,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1571,15 +1581,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1587,28 +1597,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1616,33 +1626,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1652,9 +1662,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1662,19 +1672,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1684,15 +1694,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1704,12 +1715,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1720,12 +1731,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1736,9 +1747,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1746,9 +1757,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1756,9 +1767,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1766,9 +1777,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1776,12 +1787,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1790,76 +1801,77 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1871,12 +1883,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1887,12 +1899,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1903,9 +1915,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1913,9 +1925,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1923,9 +1935,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1933,9 +1945,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1943,12 +1955,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1957,82 +1969,83 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2044,9 +2057,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2054,9 +2067,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2064,54 +2077,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/interpreter.v b/CoqOfPython/ethereum/istanbul/vm/interpreter.v
index dc57fbf..c35bb38 100644
--- a/CoqOfPython/ethereum/istanbul/vm/interpreter.v
+++ b/CoqOfPython/ethereum/istanbul/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.interpreter".
+Definition globals : Globals.t := "ethereum.istanbul.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -124,7 +126,7 @@ Axiom ethereum_istanbul_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -147,8 +149,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -170,9 +173,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -184,10 +187,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -195,44 +198,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -246,10 +249,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -262,10 +265,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -274,13 +277,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -290,12 +293,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -312,14 +315,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -327,7 +330,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -335,7 +338,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -347,22 +350,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -372,29 +375,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -402,8 +405,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -420,43 +424,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -464,24 +468,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -489,22 +493,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -524,13 +529,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -542,17 +547,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -560,10 +565,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -571,12 +576,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -588,10 +593,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -599,13 +604,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -613,22 +618,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -646,14 +652,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -661,13 +667,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/memory.v b/CoqOfPython/ethereum/istanbul/vm/memory.v
index 743e878..a1df5bc 100644
--- a/CoqOfPython/ethereum/istanbul/vm/memory.v
+++ b/CoqOfPython/ethereum/istanbul/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.memory".
+Definition globals : Globals.t := "ethereum.istanbul.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/__init__.v
index 1419ef4..d4f03ea 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/alt_bn128.v
index e074092..3827717 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_istanbul_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.istanbul.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/blake2f.v
index da836ff..61318dc 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_istanbul_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.istanbul.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ecrecover.v
index de71626..1cee0f2 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_istanbul_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.istanbul.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/identity.v
index 894529f..2387288 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_istanbul_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.istanbul.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/mapping.v
index d88667d..a8e754d 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/modexp.v
index 6178170..575a5b6 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,7 +37,7 @@ Axiom ethereum_istanbul_vm_memory_imports_buffer_read :
 
 Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -44,34 +46,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -87,21 +90,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -117,21 +120,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -148,36 +151,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -192,7 +195,7 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "exp_length" |),
+          M.get_name (| globals, locals_stack, "exp_length" |),
           Constant.int 32
         |),
       (* then *)
@@ -200,15 +203,15 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   Constant.int 0;
                   BinOp.sub (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                       make_list [],
                       make_dict []
                     |),
@@ -227,16 +230,16 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               BinOp.add (|
                 BinOp.mult (|
                   Constant.int 8,
                   BinOp.sub (|
                     M.call (|
-                      M.get_name (| globals, "int" |),
+                      M.get_name (| globals, locals_stack, "int" |),
                       make_list [
-                        M.get_name (| globals, "exp_length" |)
+                        M.get_name (| globals, locals_stack, "exp_length" |)
                       ],
                       make_dict []
                     |),
@@ -244,12 +247,12 @@ Definition modexp : Value.t -> Value.t -> M :=
                   |)
                 |),
                 M.call (|
-                  M.get_name (| globals, "max" |),
+                  M.get_name (| globals, locals_stack, "max" |),
                   make_list [
                     Constant.int 0;
                     BinOp.sub (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                         make_list [],
                         make_dict []
                       |),
@@ -266,22 +269,22 @@ Definition modexp : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.floor_div (|
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "get_mult_complexity" |),
+            M.get_name (| globals, locals_stack, "get_mult_complexity" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "max" |),
+                    M.get_name (| globals, locals_stack, "max" |),
                     make_list [
-                      M.get_name (| globals, "base_length" |);
-                      M.get_name (| globals, "modulus_length" |)
+                      M.get_name (| globals, locals_stack, "base_length" |);
+                      M.get_name (| globals, locals_stack, "modulus_length" |)
                     ],
                     make_dict []
                   |)
@@ -292,11 +295,11 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "adjusted_exp_length" |);
+              M.get_name (| globals, locals_stack, "adjusted_exp_length" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 1
                 ],
@@ -306,7 +309,7 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |)
         |),
-        M.get_name (| globals, "GQUADDIVISOR" |)
+        M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
       |)
     ],
     make_dict []
@@ -316,12 +319,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -329,9 +332,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -347,20 +350,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -371,14 +374,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -389,21 +392,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -415,39 +418,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -455,7 +458,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -466,8 +469,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_mult_complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing Karatsuba multiplication.
     " in
@@ -475,14 +479,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 64
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.pow (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 2
           |)
         |) in
@@ -493,7 +497,7 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "x" |),
+              M.get_name (| globals, locals_stack, "x" |),
               Constant.int 1024
             |),
           (* then *)
@@ -503,14 +507,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 4
                   |),
                   BinOp.mult (|
                     Constant.int 96,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 3072
@@ -524,14 +528,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 16
                   |),
                   BinOp.mult (|
                     Constant.int 480,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 199680
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ripemd160.v
index 9355562..5e50193 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_istanbul_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.istanbul.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/sha256.v
index 36128c8..e2ba3ba 100644
--- a/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/istanbul/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.istanbul.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_istanbul_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.istanbul.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/istanbul/vm/runtime.v b/CoqOfPython/ethereum/istanbul/vm/runtime.v
index 88abdd0..d074968 100644
--- a/CoqOfPython/ethereum/istanbul/vm/runtime.v
+++ b/CoqOfPython/ethereum/istanbul/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.runtime".
+Definition globals : Globals.t := "ethereum.istanbul.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_istanbul_vm_instructions_imports_Ops :
   IsImported globals "ethereum.istanbul.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/istanbul/vm/stack.v b/CoqOfPython/ethereum/istanbul/vm/stack.v
index 8a72fb1..5e0db23 100644
--- a/CoqOfPython/ethereum/istanbul/vm/stack.v
+++ b/CoqOfPython/ethereum/istanbul/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.istanbul.vm.stack".
+Definition globals : Globals.t := "ethereum.istanbul.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_istanbul_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.istanbul.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/__init__.v b/CoqOfPython/ethereum/london/__init__.v
index d0a16e4..1653ae0 100644
--- a/CoqOfPython/ethereum/london/__init__.v
+++ b/CoqOfPython/ethereum/london/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.__init__".
+Definition globals : Globals.t := "ethereum.london.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -13,7 +15,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 12965000
     ],
diff --git a/CoqOfPython/ethereum/london/blocks.v b/CoqOfPython/ethereum/london/blocks.v
index acc6316..9c5e31a 100644
--- a/CoqOfPython/ethereum/london/blocks.v
+++ b/CoqOfPython/ethereum/london/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.blocks".
+Definition globals : Globals.t := "ethereum.london.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/london/bloom.v b/CoqOfPython/ethereum/london/bloom.v
index ede68b4..8048cd3 100644
--- a/CoqOfPython/ethereum/london/bloom.v
+++ b/CoqOfPython/ethereum/london/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.bloom".
+Definition globals : Globals.t := "ethereum.london.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_london_fork_types_imports_Bloom :
   IsImported globals "ethereum.london.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/fork.v b/CoqOfPython/ethereum/london/fork.v
index 2a268b2..0213a39 100644
--- a/CoqOfPython/ethereum/london/fork.v
+++ b/CoqOfPython/ethereum/london/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.fork".
+Definition globals : Globals.t := "ethereum.london.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -152,7 +154,7 @@ Axiom ethereum_london_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -184,7 +186,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -206,10 +208,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -231,8 +233,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -252,13 +255,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -281,7 +285,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -292,9 +296,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -316,17 +320,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -339,13 +343,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -356,20 +360,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -394,112 +399,112 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -508,9 +513,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -519,9 +524,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -535,8 +540,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas"; "is_fork_block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas"; "is_fork_block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -561,14 +567,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_name (| globals, "is_fork_block" |),
+        M.get_name (| globals, locals_stack, "is_fork_block" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "INITIAL_BASE_FEE" |)
+              M.get_name (| globals, locals_stack, "INITIAL_BASE_FEE" |)
             ],
             make_dict []
           |)
@@ -581,22 +587,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -604,14 +610,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -620,40 +626,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -663,8 +669,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -673,36 +679,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -711,9 +717,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -721,8 +727,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -741,131 +748,131 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "is_fork_block" ,
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
-        M.get_field (| M.get_name (| globals, "FORK_CRITERIA" |), "block_number" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "FORK_CRITERIA" |), "block_number" |)
       |)
     |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |);
-          M.get_name (| globals, "is_fork_block" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |);
+          M.get_name (| globals, locals_stack, "is_fork_block" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -874,28 +881,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -921,27 +929,27 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |);
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -949,8 +957,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -968,9 +977,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -978,25 +987,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -1005,41 +1014,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -1067,23 +1077,23 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1092,46 +1102,46 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -1140,38 +1150,39 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -1195,7 +1206,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -1204,10 +1215,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1217,9 +1228,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1232,10 +1243,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1245,9 +1256,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1257,7 +1268,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.return_ (|
-              M.get_name (| globals, "receipt" |)
+              M.get_name (| globals, locals_stack, "receipt" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -1276,8 +1287,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1322,22 +1334,22 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1346,16 +1358,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1363,9 +1375,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1373,14 +1385,14 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1388,18 +1400,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1407,49 +1419,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1458,56 +1470,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1518,8 +1530,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1544,27 +1557,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1573,9 +1586,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1593,46 +1606,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1643,19 +1656,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1664,23 +1677,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1688,16 +1701,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1711,13 +1724,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1732,11 +1745,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1744,88 +1757,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1838,8 +1851,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1868,44 +1882,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1917,19 +1931,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1942,8 +1956,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1971,30 +1986,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -2003,10 +2018,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
@@ -2015,8 +2030,8 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -2025,100 +2040,100 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "effective_gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "effective_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2126,7 +2141,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -2135,10 +2150,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2146,25 +2161,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -2188,14 +2203,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2203,10 +2218,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -2214,20 +2229,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -2236,17 +2251,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2254,41 +2269,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -2296,31 +2311,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -2331,20 +2346,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -2357,14 +2372,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2376,27 +2391,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -2412,13 +2427,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -2447,17 +2463,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -2472,8 +2488,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2502,14 +2519,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2517,7 +2534,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2525,7 +2542,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2539,9 +2556,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2552,7 +2569,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2571,10 +2588,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2582,26 +2599,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2617,17 +2634,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2636,8 +2653,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2660,47 +2678,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2708,10 +2726,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2719,19 +2737,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2741,18 +2759,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2764,58 +2782,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2832,10 +2850,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2844,15 +2862,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2867,10 +2885,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2879,15 +2897,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2906,13 +2924,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2927,8 +2945,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2944,12 +2963,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2960,8 +2979,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2979,19 +2999,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -3007,8 +3027,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -3024,14 +3045,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3043,8 +3064,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -3060,14 +3082,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -3079,8 +3101,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -3114,12 +3137,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -3130,8 +3153,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -3162,18 +3186,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3190,10 +3214,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -3210,8 +3234,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -3229,8 +3253,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -3274,21 +3299,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -3298,11 +3323,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -3320,13 +3345,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -3335,13 +3360,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -3352,7 +3377,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -3362,7 +3387,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -3372,13 +3397,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/london/fork_types.v b/CoqOfPython/ethereum/london/fork_types.v
index 3c5e125..2dbc932 100644
--- a/CoqOfPython/ethereum/london/fork_types.v
+++ b/CoqOfPython/ethereum/london/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.fork_types".
+Definition globals : Globals.t := "ethereum.london.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/london/state.v b/CoqOfPython/ethereum/london/state.v
index afa32da..4eab149 100644
--- a/CoqOfPython/ethereum/london/state.v
+++ b/CoqOfPython/ethereum/london/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.state".
+Definition globals : Globals.t := "ethereum.london.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/transactions.v b/CoqOfPython/ethereum/london/transactions.v
index 432578b..bf51ad0 100644
--- a/CoqOfPython/ethereum/london/transactions.v
+++ b/CoqOfPython/ethereum/london/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.transactions".
+Definition globals : Globals.t := "ethereum.london.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,14 +99,15 @@ Definition FeeMarketTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -112,17 +115,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -131,10 +134,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -144,9 +147,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -159,10 +162,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -172,9 +175,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -184,7 +187,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "Exception" |),
+                  M.get_name (| globals, locals_stack, "Exception" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -199,8 +202,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -208,10 +212,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -222,7 +226,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -231,11 +235,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -252,7 +256,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -261,11 +265,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -277,7 +281,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
-                let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                 M.pure Constant.None_
               )) |) in
             M.pure Constant.None_
@@ -286,7 +290,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/london/trie.v b/CoqOfPython/ethereum/london/trie.v
index dac8ce1..ba27f23 100644
--- a/CoqOfPython/ethereum/london/trie.v
+++ b/CoqOfPython/ethereum/london/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.trie".
+Definition globals : Globals.t := "ethereum.london.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_london_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,34 +124,34 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -187,14 +189,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -218,7 +221,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -234,10 +237,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -246,13 +249,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -261,10 +264,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -273,13 +276,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -288,10 +291,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -300,9 +303,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -310,7 +313,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -327,9 +330,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -339,9 +342,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -350,16 +353,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -369,8 +372,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -380,25 +384,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -410,10 +414,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -421,13 +425,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -442,27 +446,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -486,8 +490,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -504,14 +509,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -522,8 +527,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -543,8 +549,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -552,14 +558,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -571,18 +577,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -602,10 +609,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -613,21 +620,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -640,11 +648,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -652,12 +660,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -665,7 +673,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -680,9 +688,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -690,8 +698,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -728,7 +737,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -739,9 +748,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -752,13 +761,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -766,15 +775,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -784,20 +793,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -815,7 +824,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -823,13 +832,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -838,15 +847,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -856,20 +865,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -887,9 +896,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -897,8 +906,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -915,14 +925,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -933,26 +943,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -960,17 +970,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -982,9 +992,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -992,8 +1002,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1014,9 +1025,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1025,25 +1036,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1051,13 +1062,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1071,9 +1082,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1081,13 +1092,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1095,15 +1106,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1113,22 +1124,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1137,13 +1148,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1164,10 +1176,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1175,14 +1187,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1200,12 +1212,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1218,12 +1230,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1235,18 +1247,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1256,8 +1268,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1281,9 +1294,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1302,12 +1315,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1320,9 +1333,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1333,24 +1346,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1360,8 +1373,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1369,31 +1382,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1408,7 +1421,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1429,7 +1442,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1437,30 +1450,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1480,9 +1493,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1490,7 +1503,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1508,21 +1521,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1530,19 +1543,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1551,8 +1564,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1561,17 +1574,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1584,10 +1597,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/utils/__init__.v b/CoqOfPython/ethereum/london/utils/__init__.v
index 3cb26eb..75f82ef 100644
--- a/CoqOfPython/ethereum/london/utils/__init__.v
+++ b/CoqOfPython/ethereum/london/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.utils.__init__".
+Definition globals : Globals.t := "ethereum.london.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/london/utils/address.v b/CoqOfPython/ethereum/london/utils/address.v
index f43bd88..89e5262 100644
--- a/CoqOfPython/ethereum/london/utils/address.v
+++ b/CoqOfPython/ethereum/london/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.utils.address".
+Definition globals : Globals.t := "ethereum.london.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_london_fork_types_imports_Address :
   IsImported globals "ethereum.london.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/utils/hexadecimal.v b/CoqOfPython/ethereum/london/utils/hexadecimal.v
index 94f210a..c646db7 100644
--- a/CoqOfPython/ethereum/london/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/london/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.london.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_london_fork_types_imports_Root :
   IsImported globals "ethereum.london.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/london/utils/message.v b/CoqOfPython/ethereum/london/utils/message.v
index 573dcf4..3c0fb98 100644
--- a/CoqOfPython/ethereum/london/utils/message.v
+++ b/CoqOfPython/ethereum/london/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.utils.message".
+Definition globals : Globals.t := "ethereum.london.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_london_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.london.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/vm/__init__.v b/CoqOfPython/ethereum/london/vm/__init__.v
index 9d60f4a..e177f5b 100644
--- a/CoqOfPython/ethereum/london/vm/__init__.v
+++ b/CoqOfPython/ethereum/london/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.__init__".
+Definition globals : Globals.t := "ethereum.london.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/exceptions.v b/CoqOfPython/ethereum/london/vm/exceptions.v
index 277efd6..9c5da7a 100644
--- a/CoqOfPython/ethereum/london/vm/exceptions.v
+++ b/CoqOfPython/ethereum/london/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.exceptions".
+Definition globals : Globals.t := "ethereum.london.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/london/vm/gas.v b/CoqOfPython/ethereum/london/vm/gas.v
index 08eb313..5e6fbd5 100644
--- a/CoqOfPython/ethereum/london/vm/gas.v
+++ b/CoqOfPython/ethereum/london/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.gas".
+Definition globals : Globals.t := "ethereum.london.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_london_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -326,7 +328,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -336,7 +338,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -356,7 +358,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -376,7 +378,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -406,7 +408,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -416,7 +418,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -426,7 +428,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -465,8 +467,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -479,13 +482,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -496,22 +499,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -521,8 +524,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -542,9 +546,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -554,15 +558,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -571,16 +575,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,12 +624,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -634,14 +639,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -655,9 +660,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -665,20 +670,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -691,8 +696,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -706,16 +711,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -723,9 +728,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -734,13 +739,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -750,10 +755,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -761,8 +766,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -793,13 +799,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -807,32 +813,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -846,18 +852,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -868,15 +874,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -885,8 +891,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -902,9 +909,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/london/vm/instructions/__init__.v b/CoqOfPython/ethereum/london/vm/instructions/__init__.v
index ed385be..3d27c13 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/london/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/london/vm/instructions/arithmetic.v
index 1b66ceb..ce2405b 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/bitwise.v b/CoqOfPython/ethereum/london/vm/instructions/bitwise.v
index 02bebb6..dfc49eb 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/block.v b/CoqOfPython/ethereum/london/vm/instructions/block.v
index e3bee4c..a61620f 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/comparison.v b/CoqOfPython/ethereum/london/vm/instructions/comparison.v
index 4a78f2d..75c4043 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/control_flow.v b/CoqOfPython/ethereum/london/vm/instructions/control_flow.v
index 263e036..b27e30e 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/environment.v b/CoqOfPython/ethereum/london/vm/instructions/environment.v
index f91ee73..69d9988 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,42 +1472,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1500,21 +1520,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1523,7 +1543,7 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/keccak.v b/CoqOfPython/ethereum/london/vm/instructions/keccak.v
index ddef676..6f443d1 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/log.v b/CoqOfPython/ethereum/london/vm/instructions/log.v
index 8122664..24b0aa1 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_london_vm_stack_imports_pop :
   IsImported globals "ethereum.london.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/london/vm/instructions/memory.v b/CoqOfPython/ethereum/london/vm/instructions/memory.v
index 494a8b3..35a385e 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/stack.v b/CoqOfPython/ethereum/london/vm/instructions/stack.v
index b5976e8..8bc2b0c 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_london_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.london.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/london/vm/instructions/storage.v b/CoqOfPython/ethereum/london/vm/instructions/storage.v
index ed374ae..e8cbac7 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/instructions/system.v b/CoqOfPython/ethereum/london/vm/instructions/system.v
index a747adf..2cc7d6e 100644
--- a/CoqOfPython/ethereum/london/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/london/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.london.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,28 +107,29 @@ Axiom ethereum_london_vm_stack_imports_push :
   IsImported globals "ethereum.london.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -136,32 +139,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -171,15 +174,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -195,10 +198,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -208,15 +211,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -237,29 +240,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -279,27 +282,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -307,10 +310,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -318,27 +321,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -351,25 +354,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -381,8 +384,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -394,9 +398,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -404,9 +408,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -414,9 +418,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -424,46 +428,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -472,26 +476,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -506,9 +511,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -516,9 +521,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -526,9 +531,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -537,9 +542,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -550,11 +555,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -564,12 +569,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -580,43 +585,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -625,26 +630,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -656,9 +662,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -666,9 +672,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -676,63 +682,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -740,24 +747,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -777,11 +784,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -789,10 +796,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -800,7 +807,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -808,10 +815,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -819,27 +826,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -852,23 +859,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -882,16 +889,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -903,14 +910,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -919,8 +926,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -932,12 +940,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -948,12 +956,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -964,9 +972,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -974,9 +982,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -984,9 +992,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -994,9 +1002,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1004,9 +1012,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1014,12 +1022,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1029,28 +1037,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1060,16 +1068,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1077,7 +1085,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1085,7 +1093,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1093,13 +1101,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1107,56 +1115,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1165,25 +1173,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1192,17 +1200,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1212,32 +1220,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1245,14 +1253,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1264,12 +1273,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1280,12 +1289,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1296,9 +1305,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,9 +1335,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1336,26 +1345,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1365,28 +1374,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1395,13 +1404,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1409,58 +1418,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1469,17 +1478,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1489,32 +1498,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1522,14 +1531,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1541,12 +1551,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1556,28 +1566,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1589,20 +1599,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1615,7 +1625,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1623,32 +1633,32 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1656,33 +1666,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1692,9 +1702,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1702,19 +1712,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1724,15 +1734,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1744,12 +1755,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1760,12 +1771,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1776,9 +1787,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1786,9 +1797,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1796,9 +1807,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1806,9 +1817,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1816,12 +1827,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1831,104 +1842,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1940,12 +1952,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1956,12 +1968,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1972,9 +1984,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1982,9 +1994,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1992,9 +2004,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2002,9 +2014,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2012,12 +2024,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2027,110 +2039,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2142,9 +2155,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2152,9 +2165,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2162,54 +2175,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/interpreter.v b/CoqOfPython/ethereum/london/vm/interpreter.v
index 6398f45..01a4ef3 100644
--- a/CoqOfPython/ethereum/london/vm/interpreter.v
+++ b/CoqOfPython/ethereum/london/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.interpreter".
+Definition globals : Globals.t := "ethereum.london.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -126,7 +128,7 @@ Axiom ethereum_london_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -149,8 +151,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -172,9 +175,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -186,10 +189,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -197,44 +200,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -248,10 +251,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -264,10 +267,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -276,13 +279,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -292,12 +295,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -314,14 +317,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -329,7 +332,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -337,7 +340,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -349,22 +352,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -374,29 +377,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -404,8 +407,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -422,43 +426,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -466,24 +470,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -491,22 +495,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -526,13 +531,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -544,17 +549,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -562,10 +567,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -573,12 +578,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -590,10 +595,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -601,13 +606,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -615,22 +620,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -648,14 +654,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -663,13 +669,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/memory.v b/CoqOfPython/ethereum/london/vm/memory.v
index 69b3e08..84e2145 100644
--- a/CoqOfPython/ethereum/london/vm/memory.v
+++ b/CoqOfPython/ethereum/london/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.memory".
+Definition globals : Globals.t := "ethereum.london.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/__init__.v
index 3866316..1bdd648 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/alt_bn128.v
index 40ca063..5026931 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_london_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.london.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/blake2f.v
index 19507e0..3cbabcc 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_london_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.london.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/ecrecover.v
index 30d0b1a..cae6267 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_london_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.london.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/identity.v
index df382e7..421b701 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_london_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.london.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/mapping.v
index 021da76..2b1cffd 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/modexp.v
index 638770d..9c7c360 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/ripemd160.v
index 9c8567e..6a3952c 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_london_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.london.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/london/vm/precompiled_contracts/sha256.v
index ea0b74a..f1b4b78 100644
--- a/CoqOfPython/ethereum/london/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/london/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.london.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_london_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.london.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/london/vm/runtime.v b/CoqOfPython/ethereum/london/vm/runtime.v
index 0b7292e..431534c 100644
--- a/CoqOfPython/ethereum/london/vm/runtime.v
+++ b/CoqOfPython/ethereum/london/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.runtime".
+Definition globals : Globals.t := "ethereum.london.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_london_vm_instructions_imports_Ops :
   IsImported globals "ethereum.london.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/london/vm/stack.v b/CoqOfPython/ethereum/london/vm/stack.v
index 745ac5c..4a1ee77 100644
--- a/CoqOfPython/ethereum/london/vm/stack.v
+++ b/CoqOfPython/ethereum/london/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.london.vm.stack".
+Definition globals : Globals.t := "ethereum.london.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_london_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.london.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/__init__.v b/CoqOfPython/ethereum/muir_glacier/__init__.v
index bb77935..0fc2600 100644
--- a/CoqOfPython/ethereum/muir_glacier/__init__.v
+++ b/CoqOfPython/ethereum/muir_glacier/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.__init__".
+Definition globals : Globals.t := "ethereum.muir_glacier.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -13,7 +15,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 9200000
     ],
diff --git a/CoqOfPython/ethereum/muir_glacier/blocks.v b/CoqOfPython/ethereum/muir_glacier/blocks.v
index 2a404eb..7b797d3 100644
--- a/CoqOfPython/ethereum/muir_glacier/blocks.v
+++ b/CoqOfPython/ethereum/muir_glacier/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.blocks".
+Definition globals : Globals.t := "ethereum.muir_glacier.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/muir_glacier/bloom.v b/CoqOfPython/ethereum/muir_glacier/bloom.v
index ee72a93..0b50d31 100644
--- a/CoqOfPython/ethereum/muir_glacier/bloom.v
+++ b/CoqOfPython/ethereum/muir_glacier/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.bloom".
+Definition globals : Globals.t := "ethereum.muir_glacier.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_muir_glacier_fork_types_imports_Bloom :
   IsImported globals "ethereum.muir_glacier.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/fork.v b/CoqOfPython/ethereum/muir_glacier/fork.v
index 7b80d97..1e7076d 100644
--- a/CoqOfPython/ethereum/muir_glacier/fork.v
+++ b/CoqOfPython/ethereum/muir_glacier/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.fork".
+Definition globals : Globals.t := "ethereum.muir_glacier.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_muir_glacier_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 2,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -176,10 +178,10 @@ Definition BOMB_DELAY_BLOCKS : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -201,8 +203,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -222,13 +225,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -251,7 +255,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -262,9 +266,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -286,17 +290,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -309,13 +313,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -326,20 +330,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -364,111 +369,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -477,9 +482,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -488,9 +493,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -504,8 +509,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -526,101 +532,101 @@ Definition validate_header : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_has_ommers" ,
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "parent_header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |);
-          M.get_name (| globals, "parent_has_ommers" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |);
+          M.get_name (| globals, locals_stack, "parent_has_ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -629,28 +635,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -676,26 +683,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -703,8 +710,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -722,9 +730,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -732,25 +740,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -759,41 +767,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -817,35 +826,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -869,13 +879,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -890,8 +900,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -934,51 +945,51 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -986,18 +997,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1005,49 +1016,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1056,56 +1067,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1116,8 +1127,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1142,27 +1154,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1171,9 +1183,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1191,46 +1203,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1241,19 +1253,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1262,23 +1274,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1286,16 +1298,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1309,13 +1321,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1330,11 +1342,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1342,88 +1354,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1436,8 +1448,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1466,44 +1479,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1515,19 +1528,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1540,8 +1553,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1569,30 +1583,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1600,98 +1614,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1699,10 +1713,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1710,20 +1724,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1732,10 +1746,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1743,41 +1757,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1785,31 +1799,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1820,20 +1834,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1846,14 +1860,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1865,27 +1879,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1901,13 +1915,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1936,17 +1951,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1961,8 +1976,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1991,14 +2007,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2006,7 +2022,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2014,7 +2030,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2028,9 +2044,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2041,7 +2057,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2054,14 +2070,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2070,8 +2086,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2094,47 +2111,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2143,12 +2160,12 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -2158,18 +2175,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_pre155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |)
+                  M.get_name (| globals, locals_stack, "tx" |)
                 ],
                 make_dict []
               |)
@@ -2181,58 +2198,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 35
                 |),
                 BinOp.mult (|
-                  M.get_name (| globals, "chain_id" |),
+                  M.get_name (| globals, locals_stack, "chain_id" |),
                   Constant.int 2
                 |)
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |);
-                  M.get_name (| globals, "chain_id" |)
+                  M.get_name (| globals, locals_stack, "tx" |);
+                  M.get_name (| globals, locals_stack, "chain_id" |)
                 ],
                 make_dict []
               |)
@@ -2244,13 +2261,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2265,8 +2282,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2282,12 +2300,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2298,8 +2316,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2317,19 +2336,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2345,8 +2364,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2380,12 +2400,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2396,8 +2416,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2428,18 +2449,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2456,10 +2477,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2476,8 +2497,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2495,8 +2516,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty"; "parent_has_ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2540,21 +2562,21 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
                             (* if *)
               M.if_then_else (|
-                M.get_name (| globals, "parent_has_ommers" |),
+                M.get_name (| globals, locals_stack, "parent_has_ommers" |),
               (* then *)
               ltac:(M.monadic (
 Constant.int 2
@@ -2564,11 +2586,11 @@ Constant.int 1
               )) |),
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2586,13 +2608,13 @@ Constant.int 1
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2601,13 +2623,13 @@ Constant.int 1
         BinOp.floor_div (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
-                M.get_name (| globals, "block_number" |)
+                M.get_name (| globals, locals_stack, "block_number" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "BOMB_DELAY_BLOCKS" |)
+            M.get_name (| globals, locals_stack, "BOMB_DELAY_BLOCKS" |)
           |),
           Constant.int 100000
         |),
@@ -2618,7 +2640,7 @@ Constant.int 1
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2628,7 +2650,7 @@ Constant.int 1
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2638,13 +2660,13 @@ Constant.int 1
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/muir_glacier/fork_types.v b/CoqOfPython/ethereum/muir_glacier/fork_types.v
index 100f313..54e2920 100644
--- a/CoqOfPython/ethereum/muir_glacier/fork_types.v
+++ b/CoqOfPython/ethereum/muir_glacier/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.fork_types".
+Definition globals : Globals.t := "ethereum.muir_glacier.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/muir_glacier/state.v b/CoqOfPython/ethereum/muir_glacier/state.v
index 28df1ec..a29a84b 100644
--- a/CoqOfPython/ethereum/muir_glacier/state.v
+++ b/CoqOfPython/ethereum/muir_glacier/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.state".
+Definition globals : Globals.t := "ethereum.muir_glacier.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1163,19 +1191,20 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1194,14 +1223,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1214,18 +1243,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1234,7 +1263,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1242,7 +1271,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1255,10 +1284,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1266,14 +1295,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/transactions.v b/CoqOfPython/ethereum/muir_glacier/transactions.v
index 0443ebc..b62f546 100644
--- a/CoqOfPython/ethereum/muir_glacier/transactions.v
+++ b/CoqOfPython/ethereum/muir_glacier/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.transactions".
+Definition globals : Globals.t := "ethereum.muir_glacier.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/muir_glacier/trie.v b/CoqOfPython/ethereum/muir_glacier/trie.v
index 5e9b0cd..864cfc2 100644
--- a/CoqOfPython/ethereum/muir_glacier/trie.v
+++ b/CoqOfPython/ethereum/muir_glacier/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.trie".
+Definition globals : Globals.t := "ethereum.muir_glacier.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_muir_glacier_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/utils/__init__.v b/CoqOfPython/ethereum/muir_glacier/utils/__init__.v
index d8eb235..21c7ec2 100644
--- a/CoqOfPython/ethereum/muir_glacier/utils/__init__.v
+++ b/CoqOfPython/ethereum/muir_glacier/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.utils.__init__".
+Definition globals : Globals.t := "ethereum.muir_glacier.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/muir_glacier/utils/address.v b/CoqOfPython/ethereum/muir_glacier/utils/address.v
index 7c8c1f0..eb42dd0 100644
--- a/CoqOfPython/ethereum/muir_glacier/utils/address.v
+++ b/CoqOfPython/ethereum/muir_glacier/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.utils.address".
+Definition globals : Globals.t := "ethereum.muir_glacier.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_muir_glacier_fork_types_imports_Address :
   IsImported globals "ethereum.muir_glacier.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/utils/hexadecimal.v b/CoqOfPython/ethereum/muir_glacier/utils/hexadecimal.v
index 56e0dcc..42f88f5 100644
--- a/CoqOfPython/ethereum/muir_glacier/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/muir_glacier/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.muir_glacier.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_muir_glacier_fork_types_imports_Root :
   IsImported globals "ethereum.muir_glacier.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/muir_glacier/utils/message.v b/CoqOfPython/ethereum/muir_glacier/utils/message.v
index e7c7551..4f9fc3a 100644
--- a/CoqOfPython/ethereum/muir_glacier/utils/message.v
+++ b/CoqOfPython/ethereum/muir_glacier/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.utils.message".
+Definition globals : Globals.t := "ethereum.muir_glacier.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_muir_glacier_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.muir_glacier.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -85,10 +88,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -97,20 +100,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -124,7 +127,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -133,7 +136,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -142,10 +145,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -153,19 +156,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -174,14 +177,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -192,7 +195,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -204,7 +207,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/__init__.v b/CoqOfPython/ethereum/muir_glacier/vm/__init__.v
index e34d6a5..937f07b 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/__init__.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.__init__".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -95,8 +97,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -109,30 +112,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -140,19 +143,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,8 +167,9 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -180,15 +184,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -201,8 +205,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -210,19 +214,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -238,7 +242,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/exceptions.v b/CoqOfPython/ethereum/muir_glacier/vm/exceptions.v
index 9843a2b..7261cd7 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/exceptions.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.exceptions".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/gas.v b/CoqOfPython/ethereum/muir_glacier/vm/gas.v
index 6ebc8c4..66a408e 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/gas.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.gas".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_muir_glacier_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 800
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -436,7 +438,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -446,7 +448,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -456,7 +458,7 @@ Definition GAS_CODE_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -466,7 +468,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -495,8 +497,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -509,13 +512,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -526,22 +529,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -551,8 +554,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -572,9 +576,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -584,15 +588,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -601,16 +605,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -629,7 +634,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -639,7 +644,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -649,12 +654,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -664,14 +669,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -685,9 +690,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -695,20 +700,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -721,8 +726,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -736,16 +741,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -753,9 +758,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -764,13 +769,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -780,10 +785,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -791,8 +796,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -823,13 +829,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -837,32 +843,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -876,18 +882,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -898,15 +904,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -915,8 +921,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -932,9 +939,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/__init__.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/__init__.v
index d7a2ea0..2e0d4f9 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/arithmetic.v
index 6e651f5..e1e2fbf 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/bitwise.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/bitwise.v
index 7fff3d6..218ede8 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/block.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/block.v
index 167e4e0..3e5efa5 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,14 +350,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -361,21 +370,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -384,7 +393,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/comparison.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/comparison.v
index 63bffa3..9c05bcd 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/control_flow.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/control_flow.v
index 50f5c02..f7bab8a 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/environment.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/environment.v
index dc3f915..e783002 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -78,8 +80,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -91,21 +94,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -114,14 +117,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -134,12 +138,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -148,42 +152,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -196,21 +201,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -219,14 +224,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -238,21 +244,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -261,14 +267,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -280,31 +287,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -318,30 +326,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -352,13 +360,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -367,14 +375,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -386,24 +395,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -415,14 +424,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -438,9 +448,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -448,9 +458,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -458,9 +468,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -469,12 +479,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -487,76 +497,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -568,24 +579,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -597,14 +608,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -620,9 +632,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -630,9 +642,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -640,9 +652,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -651,12 +663,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -669,76 +681,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -750,21 +763,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -773,14 +786,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -793,12 +807,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -807,26 +821,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -838,23 +852,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -867,12 +882,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -883,9 +898,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -893,9 +908,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -903,9 +918,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -914,12 +929,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -932,52 +947,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -985,34 +1000,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1023,24 +1039,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1052,14 +1068,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1071,9 +1088,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1081,9 +1098,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1091,9 +1108,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1102,12 +1119,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1120,108 +1137,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1232,12 +1250,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1246,20 +1264,20 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_CODE_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_CODE_HASH" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1268,15 +1286,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1289,12 +1307,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1305,23 +1323,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1333,35 +1352,35 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/keccak.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/keccak.v
index a317bc4..3a872ed 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/log.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/log.v
index 6d8d000..378ef42 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_pop :
   IsImported globals "ethereum.muir_glacier.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/memory.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/memory.v
index c12ac45..deda339 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/stack.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/stack.v
index c20b432..6b1c23c 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_muir_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.muir_glacier.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/storage.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/storage.v
index dd601c1..f8cea22 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -54,8 +56,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -70,9 +73,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -81,43 +84,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -131,9 +135,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -144,32 +148,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -177,11 +181,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -191,13 +195,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -207,21 +211,21 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_cost" ,
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_cost" ,
-              M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -230,7 +234,7 @@ Definition sstore : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -238,8 +242,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -248,18 +252,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -270,11 +274,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -289,12 +293,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -303,11 +307,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -321,8 +325,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -330,20 +334,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_SLOAD" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
       |)
     ],
     make_dict []
@@ -354,13 +358,13 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-        M.get_name (| globals, "GAS_SLOAD" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+        M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
       |)
     ],
     make_dict []
@@ -379,34 +383,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/instructions/system.v b/CoqOfPython/ethereum/muir_glacier/vm/instructions/system.v
index 087a683..25f3e39 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,8 +107,9 @@ Axiom ethereum_muir_glacier_vm_stack_imports_push :
   IsImported globals "ethereum.muir_glacier.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
@@ -114,12 +117,12 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -129,32 +132,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -164,15 +167,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -188,10 +191,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -201,15 +204,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -230,29 +233,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -272,27 +275,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -300,10 +303,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -311,27 +314,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -344,25 +347,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -374,8 +377,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -387,9 +391,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,9 +401,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -407,9 +411,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -417,46 +421,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -465,26 +469,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -499,9 +504,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -509,9 +514,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -519,9 +524,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -530,9 +535,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -543,11 +548,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -557,12 +562,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -573,43 +578,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -618,26 +623,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -649,9 +655,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -659,9 +665,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -669,63 +675,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -733,24 +740,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -770,11 +777,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -782,10 +789,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -793,7 +800,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -801,10 +808,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -812,27 +819,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -845,23 +852,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -875,16 +882,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -896,14 +903,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -912,8 +919,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -925,12 +933,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -941,12 +949,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -957,9 +965,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -967,9 +975,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -977,9 +985,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -987,9 +995,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -997,9 +1005,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1007,12 +1015,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1024,15 +1032,15 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             M.call (|
-              M.get_name (| globals, "is_account_alive" |),
+              M.get_name (| globals, locals_stack, "is_account_alive" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "to" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "to" |)
               ],
               make_dict []
             |)
@@ -1041,7 +1049,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1049,7 +1057,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1057,13 +1065,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1071,56 +1079,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1129,25 +1137,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1156,17 +1164,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1176,32 +1184,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1209,14 +1217,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1228,12 +1237,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1244,12 +1253,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1260,9 +1269,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1270,9 +1279,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1280,9 +1289,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1290,9 +1299,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1300,26 +1309,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1330,13 +1339,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1344,58 +1353,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1404,17 +1413,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1424,32 +1433,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1457,14 +1466,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1476,12 +1486,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1491,27 +1501,27 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1524,7 +1534,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1533,33 +1543,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1571,15 +1581,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1587,28 +1597,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1616,33 +1626,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1652,9 +1662,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1662,19 +1672,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1684,15 +1694,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1704,12 +1715,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1720,12 +1731,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1736,9 +1747,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1746,9 +1757,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1756,9 +1767,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1766,9 +1777,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1776,12 +1787,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1790,76 +1801,77 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1871,12 +1883,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1887,12 +1899,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1903,9 +1915,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1913,9 +1925,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1923,9 +1935,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1933,9 +1945,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1943,12 +1955,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1957,82 +1969,83 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2044,9 +2057,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2054,9 +2067,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2064,54 +2077,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/interpreter.v b/CoqOfPython/ethereum/muir_glacier/vm/interpreter.v
index 03f7f66..6f75fab 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/interpreter.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.interpreter".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -124,7 +126,7 @@ Axiom ethereum_muir_glacier_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -147,8 +149,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -170,9 +173,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -184,10 +187,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -195,44 +198,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -246,10 +249,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -262,10 +265,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -274,13 +277,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -290,12 +293,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -312,14 +315,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -327,7 +330,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -335,7 +338,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -347,22 +350,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -372,29 +375,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -402,8 +405,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -420,43 +424,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -464,24 +468,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -489,22 +493,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -524,13 +529,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -542,17 +547,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -560,10 +565,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -571,12 +576,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -588,10 +593,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -599,13 +604,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -613,22 +618,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -646,14 +652,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -661,13 +667,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/memory.v b/CoqOfPython/ethereum/muir_glacier/vm/memory.v
index 2bdcef4..a751b41 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/memory.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.memory".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/__init__.v
index 714a0bb..3ff4af1 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/alt_bn128.v
index e709832..b97dd68 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_muir_glacier_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.muir_glacier.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/blake2f.v
index 4a75fc0..2317e98 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_muir_glacier_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.muir_glacier.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ecrecover.v
index 8312694..39ccd83 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_muir_glacier_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.muir_glacier.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/identity.v
index f2eb008..26780a0 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_muir_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.muir_glacier.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/mapping.v
index e59e8d5..33837a2 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/modexp.v
index adf5841..a5cd08f 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,7 +37,7 @@ Axiom ethereum_muir_glacier_vm_memory_imports_buffer_read :
 
 Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -44,34 +46,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -87,21 +90,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -117,21 +120,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -148,36 +151,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -192,7 +195,7 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "exp_length" |),
+          M.get_name (| globals, locals_stack, "exp_length" |),
           Constant.int 32
         |),
       (* then *)
@@ -200,15 +203,15 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   Constant.int 0;
                   BinOp.sub (|
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                       make_list [],
                       make_dict []
                     |),
@@ -227,16 +230,16 @@ Definition modexp : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "adjusted_exp_length" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               BinOp.add (|
                 BinOp.mult (|
                   Constant.int 8,
                   BinOp.sub (|
                     M.call (|
-                      M.get_name (| globals, "int" |),
+                      M.get_name (| globals, locals_stack, "int" |),
                       make_list [
-                        M.get_name (| globals, "exp_length" |)
+                        M.get_name (| globals, locals_stack, "exp_length" |)
                       ],
                       make_dict []
                     |),
@@ -244,12 +247,12 @@ Definition modexp : Value.t -> Value.t -> M :=
                   |)
                 |),
                 M.call (|
-                  M.get_name (| globals, "max" |),
+                  M.get_name (| globals, locals_stack, "max" |),
                   make_list [
                     Constant.int 0;
                     BinOp.sub (|
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "exp_head" |), "bit_length" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "exp_head" |), "bit_length" |),
                         make_list [],
                         make_dict []
                       |),
@@ -266,22 +269,22 @@ Definition modexp : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.floor_div (|
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "get_mult_complexity" |),
+            M.get_name (| globals, locals_stack, "get_mult_complexity" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "max" |),
+                    M.get_name (| globals, locals_stack, "max" |),
                     make_list [
-                      M.get_name (| globals, "base_length" |);
-                      M.get_name (| globals, "modulus_length" |)
+                      M.get_name (| globals, locals_stack, "base_length" |);
+                      M.get_name (| globals, locals_stack, "modulus_length" |)
                     ],
                     make_dict []
                   |)
@@ -292,11 +295,11 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "adjusted_exp_length" |);
+              M.get_name (| globals, locals_stack, "adjusted_exp_length" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 1
                 ],
@@ -306,7 +309,7 @@ Definition modexp : Value.t -> Value.t -> M :=
             make_dict []
           |)
         |),
-        M.get_name (| globals, "GQUADDIVISOR" |)
+        M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
       |)
     ],
     make_dict []
@@ -316,12 +319,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -329,9 +332,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -347,20 +350,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -371,14 +374,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -389,21 +392,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -415,39 +418,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -455,7 +458,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -466,8 +469,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_mult_complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing Karatsuba multiplication.
     " in
@@ -475,14 +479,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 64
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           BinOp.pow (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 2
           |)
         |) in
@@ -493,7 +497,7 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "x" |),
+              M.get_name (| globals, locals_stack, "x" |),
               Constant.int 1024
             |),
           (* then *)
@@ -503,14 +507,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 4
                   |),
                   BinOp.mult (|
                     Constant.int 96,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 3072
@@ -524,14 +528,14 @@ Definition get_mult_complexity : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   BinOp.floor_div (|
                     BinOp.pow (|
-                      M.get_name (| globals, "x" |),
+                      M.get_name (| globals, locals_stack, "x" |),
                       Constant.int 2
                     |),
                     Constant.int 16
                   |),
                   BinOp.mult (|
                     Constant.int 480,
-                    M.get_name (| globals, "x" |)
+                    M.get_name (| globals, locals_stack, "x" |)
                   |)
                 |),
                 Constant.int 199680
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ripemd160.v
index d68f6cf..c989eeb 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_muir_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.muir_glacier.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/sha256.v
index 778e74c..3d61480 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_muir_glacier_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.muir_glacier.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/runtime.v b/CoqOfPython/ethereum/muir_glacier/vm/runtime.v
index b541b08..604a265 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/runtime.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.runtime".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_muir_glacier_vm_instructions_imports_Ops :
   IsImported globals "ethereum.muir_glacier.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/muir_glacier/vm/stack.v b/CoqOfPython/ethereum/muir_glacier/vm/stack.v
index 41a8707..39e785f 100644
--- a/CoqOfPython/ethereum/muir_glacier/vm/stack.v
+++ b/CoqOfPython/ethereum/muir_glacier/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.muir_glacier.vm.stack".
+Definition globals : Globals.t := "ethereum.muir_glacier.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_muir_glacier_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.muir_glacier.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/__init__.v b/CoqOfPython/ethereum/paris/__init__.v
index fa10075..8e64af8 100644
--- a/CoqOfPython/ethereum/paris/__init__.v
+++ b/CoqOfPython/ethereum/paris/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.__init__".
+Definition globals : Globals.t := "ethereum.paris.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -17,7 +19,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 15537394
     ],
diff --git a/CoqOfPython/ethereum/paris/blocks.v b/CoqOfPython/ethereum/paris/blocks.v
index 2aa7600..0b69d9c 100644
--- a/CoqOfPython/ethereum/paris/blocks.v
+++ b/CoqOfPython/ethereum/paris/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.blocks".
+Definition globals : Globals.t := "ethereum.paris.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/paris/bloom.v b/CoqOfPython/ethereum/paris/bloom.v
index 6f6cc6b..8ed3f2c 100644
--- a/CoqOfPython/ethereum/paris/bloom.v
+++ b/CoqOfPython/ethereum/paris/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.bloom".
+Definition globals : Globals.t := "ethereum.paris.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_paris_fork_types_imports_Bloom :
   IsImported globals "ethereum.paris.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/fork.v b/CoqOfPython/ethereum/paris/fork.v
index 442ce2d..8bef456 100644
--- a/CoqOfPython/ethereum/paris/fork.v
+++ b/CoqOfPython/ethereum/paris/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.fork".
+Definition globals : Globals.t := "ethereum.paris.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -155,10 +157,10 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -180,8 +182,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -201,13 +204,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -230,7 +234,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -241,9 +245,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -265,17 +269,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -288,13 +292,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -305,20 +309,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -343,113 +348,113 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "block" |), "ommers" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |),
         make_tuple [  ]
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "prev_randao" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "prev_randao" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -458,9 +463,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -469,9 +474,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -485,8 +490,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -509,22 +515,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -532,14 +538,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -548,40 +554,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -591,8 +597,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -601,36 +607,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -639,9 +645,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -649,8 +655,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -669,124 +676,124 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
         Constant.int 0
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |),
         Constant.bytes "0000000000000000"
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -795,21 +802,22 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -837,23 +845,23 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -862,46 +870,46 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -910,38 +918,39 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -965,7 +974,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -974,10 +983,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -987,9 +996,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1002,10 +1011,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1015,9 +1024,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1027,7 +1036,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.return_ (|
-              M.get_name (| globals, "receipt" |)
+              M.get_name (| globals, locals_stack, "receipt" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -1046,8 +1055,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1092,22 +1102,22 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1116,16 +1126,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1133,9 +1143,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1143,14 +1153,14 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1158,18 +1168,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1177,49 +1187,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1230,44 +1240,44 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1278,8 +1288,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1307,30 +1318,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1339,10 +1350,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
@@ -1351,8 +1362,8 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1361,100 +1372,100 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "effective_gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "effective_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -1462,7 +1473,7 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -1471,10 +1482,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -1482,25 +1493,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -1524,14 +1535,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1539,10 +1550,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1550,20 +1561,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1572,17 +1583,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1590,41 +1601,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1632,31 +1643,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1667,20 +1678,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1693,14 +1704,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1712,27 +1723,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1748,13 +1759,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1783,17 +1795,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1808,8 +1820,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1838,14 +1851,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1853,7 +1866,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1861,7 +1874,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -1875,9 +1888,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -1888,7 +1901,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1907,10 +1920,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -1918,26 +1931,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -1953,17 +1966,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -1972,8 +1985,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -1996,47 +2010,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2044,10 +2058,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2055,19 +2069,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2077,18 +2091,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2100,58 +2114,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2168,10 +2182,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2180,15 +2194,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2203,10 +2217,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2215,15 +2229,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2242,13 +2256,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2263,8 +2277,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2280,12 +2295,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2296,8 +2311,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2315,19 +2331,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2343,8 +2359,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2360,14 +2377,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2379,8 +2396,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -2396,14 +2414,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2415,8 +2433,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2450,12 +2469,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2466,8 +2485,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2498,18 +2518,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2526,10 +2546,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2546,8 +2566,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
diff --git a/CoqOfPython/ethereum/paris/fork_types.v b/CoqOfPython/ethereum/paris/fork_types.v
index a4242a8..b5a9c85 100644
--- a/CoqOfPython/ethereum/paris/fork_types.v
+++ b/CoqOfPython/ethereum/paris/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.fork_types".
+Definition globals : Globals.t := "ethereum.paris.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/paris/simulations/fork_types.v b/CoqOfPython/ethereum/paris/simulations/fork_types.v
new file mode 100644
index 0000000..1efcb6c
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/simulations/fork_types.v
@@ -0,0 +1,12 @@
+Require Import CoqOfPython.CoqOfPython.
+Require ethereum.simulations.base_types.
+
+Module Address.
+  Inductive t : Set :=
+  | Make (address : base_types.Bytes20.t).
+
+  Definition get (address : t) : base_types.Bytes20.t :=
+    match address with
+    | Make address => address
+    end.
+End Address.
diff --git a/CoqOfPython/ethereum/paris/simulations/state.v b/CoqOfPython/ethereum/paris/simulations/state.v
new file mode 100644
index 0000000..38f5408
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/simulations/state.v
@@ -0,0 +1,5 @@
+Require Import CoqOfPython.CoqOfPython.
+
+Module State.
+  Parameter t : Set.
+End State.
diff --git a/CoqOfPython/ethereum/paris/state.v b/CoqOfPython/ethereum/paris/state.v
index a1eda52..b08baae 100644
--- a/CoqOfPython/ethereum/paris/state.v
+++ b/CoqOfPython/ethereum/paris/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.state".
+Definition globals : Globals.t := "ethereum.paris.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -85,21 +87,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -112,12 +116,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -127,8 +131,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -138,18 +143,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -161,8 +166,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -173,9 +179,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -183,11 +189,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -199,8 +205,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -223,10 +230,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -235,31 +242,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -279,22 +287,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -309,19 +318,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -337,18 +347,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -356,8 +366,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -372,14 +383,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -389,8 +400,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -408,17 +420,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -440,9 +453,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -451,14 +464,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -473,30 +486,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -514,10 +528,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -526,9 +540,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -537,7 +551,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -545,17 +559,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -563,11 +577,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -575,14 +589,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -592,8 +606,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -609,23 +624,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -635,15 +650,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -657,13 +673,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -671,8 +687,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -691,10 +708,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -704,8 +721,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -725,10 +743,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -736,9 +754,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -747,7 +765,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -756,8 +774,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -777,10 +796,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -788,9 +807,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -800,12 +819,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -816,8 +835,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -838,10 +858,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -849,15 +869,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -867,12 +887,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -885,8 +905,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -905,10 +926,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -917,7 +938,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -931,9 +952,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -943,12 +964,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -961,28 +982,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -992,36 +1014,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1038,19 +1062,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1066,21 +1091,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1092,8 +1117,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1107,19 +1133,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1136,19 +1163,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1167,14 +1195,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1187,18 +1215,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1207,7 +1235,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1215,7 +1243,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1228,10 +1256,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1239,14 +1267,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/transactions.v b/CoqOfPython/ethereum/paris/transactions.v
index c466978..dd65a12 100644
--- a/CoqOfPython/ethereum/paris/transactions.v
+++ b/CoqOfPython/ethereum/paris/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.transactions".
+Definition globals : Globals.t := "ethereum.paris.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,14 +99,15 @@ Definition FeeMarketTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -112,17 +115,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -131,10 +134,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -144,9 +147,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -159,10 +162,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -172,9 +175,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -184,7 +187,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "Exception" |),
+                  M.get_name (| globals, locals_stack, "Exception" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -199,8 +202,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -208,10 +212,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -222,7 +226,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -231,11 +235,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -252,7 +256,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -261,11 +265,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -277,7 +281,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
-                let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                 M.pure Constant.None_
               )) |) in
             M.pure Constant.None_
@@ -286,7 +290,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/paris/trie.v b/CoqOfPython/ethereum/paris/trie.v
index 90b1e2c..7f7d685 100644
--- a/CoqOfPython/ethereum/paris/trie.v
+++ b/CoqOfPython/ethereum/paris/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.trie".
+Definition globals : Globals.t := "ethereum.paris.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_paris_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,34 +124,34 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -187,14 +189,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -218,7 +221,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -234,10 +237,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -246,13 +249,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -261,10 +264,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -273,13 +276,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -288,10 +291,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -300,9 +303,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -310,7 +313,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -327,9 +330,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -339,9 +342,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -350,16 +353,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -369,8 +372,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -380,25 +384,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -410,10 +414,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -421,13 +425,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -442,27 +446,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -486,8 +490,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -504,14 +509,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -522,8 +527,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -543,8 +549,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -552,14 +558,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -571,18 +577,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -602,10 +609,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -613,21 +620,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -640,11 +648,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -652,12 +660,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -665,7 +673,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -680,9 +688,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -690,8 +698,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -728,7 +737,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -739,9 +748,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -752,13 +761,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -766,15 +775,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -784,20 +793,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -815,7 +824,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -823,13 +832,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -838,15 +847,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -856,20 +865,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -887,9 +896,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -897,8 +906,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -915,14 +925,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -933,26 +943,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -960,17 +970,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -982,9 +992,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -992,8 +1002,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1014,9 +1025,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1025,25 +1036,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1051,13 +1062,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1071,9 +1082,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1081,13 +1092,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1095,15 +1106,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1113,22 +1124,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1137,13 +1148,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1164,10 +1176,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1175,14 +1187,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1200,12 +1212,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1218,12 +1230,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1235,18 +1247,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1256,8 +1268,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1281,9 +1294,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1302,12 +1315,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1320,9 +1333,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1333,24 +1346,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1360,8 +1373,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1369,31 +1382,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1408,7 +1421,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1429,7 +1442,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1437,30 +1450,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1480,9 +1493,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1490,7 +1503,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1508,21 +1521,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1530,19 +1543,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1551,8 +1564,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1561,17 +1574,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1584,10 +1597,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/utils/__init__.v b/CoqOfPython/ethereum/paris/utils/__init__.v
index afb5c35..21363a5 100644
--- a/CoqOfPython/ethereum/paris/utils/__init__.v
+++ b/CoqOfPython/ethereum/paris/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.utils.__init__".
+Definition globals : Globals.t := "ethereum.paris.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/paris/utils/address.v b/CoqOfPython/ethereum/paris/utils/address.v
index bd0c332..c397529 100644
--- a/CoqOfPython/ethereum/paris/utils/address.v
+++ b/CoqOfPython/ethereum/paris/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.utils.address".
+Definition globals : Globals.t := "ethereum.paris.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_paris_fork_types_imports_Address :
   IsImported globals "ethereum.paris.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/utils/hexadecimal.v b/CoqOfPython/ethereum/paris/utils/hexadecimal.v
index 62e084d..2d6e655 100644
--- a/CoqOfPython/ethereum/paris/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/paris/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.paris.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_paris_fork_types_imports_Root :
   IsImported globals "ethereum.paris.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/paris/utils/message.v b/CoqOfPython/ethereum/paris/utils/message.v
index 9e2da6d..7260c46 100644
--- a/CoqOfPython/ethereum/paris/utils/message.v
+++ b/CoqOfPython/ethereum/paris/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.utils.message".
+Definition globals : Globals.t := "ethereum.paris.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_paris_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.paris.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/vm/__init__.v b/CoqOfPython/ethereum/paris/vm/__init__.v
index 472ccd5..eb698f5 100644
--- a/CoqOfPython/ethereum/paris/vm/__init__.v
+++ b/CoqOfPython/ethereum/paris/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.__init__".
+Definition globals : Globals.t := "ethereum.paris.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/exceptions.v b/CoqOfPython/ethereum/paris/vm/exceptions.v
index 95b6cd9..3b460e3 100644
--- a/CoqOfPython/ethereum/paris/vm/exceptions.v
+++ b/CoqOfPython/ethereum/paris/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.exceptions".
+Definition globals : Globals.t := "ethereum.paris.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/paris/vm/gas.v b/CoqOfPython/ethereum/paris/vm/gas.v
index 7b37d78..a43a94d 100644
--- a/CoqOfPython/ethereum/paris/vm/gas.v
+++ b/CoqOfPython/ethereum/paris/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.gas".
+Definition globals : Globals.t := "ethereum.paris.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_paris_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -326,7 +328,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -336,7 +338,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -356,7 +358,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -376,7 +378,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -406,7 +408,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -416,7 +418,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -426,7 +428,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -465,8 +467,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -479,13 +482,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -496,22 +499,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -521,8 +524,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -542,9 +546,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -554,15 +558,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -571,16 +575,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,7 +614,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -619,12 +624,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -634,14 +639,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -655,9 +660,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -665,20 +670,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -691,8 +696,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -706,16 +711,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -723,9 +728,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -734,13 +739,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -750,10 +755,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -761,8 +766,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -793,13 +799,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -807,32 +813,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -846,18 +852,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -868,15 +874,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -885,8 +891,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -902,9 +909,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/__init__.v b/CoqOfPython/ethereum/paris/vm/instructions/__init__.v
index 8cfce01..14189e3 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/paris/vm/instructions/arithmetic.v
index 3996ed7..bac5812 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/bitwise.v b/CoqOfPython/ethereum/paris/vm/instructions/bitwise.v
index 68e07c4..929ae9e 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/block.v b/CoqOfPython/ethereum/paris/vm/instructions/block.v
index 5869617..e351ba7 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -57,18 +60,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -77,14 +80,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -102,23 +105,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -127,14 +130,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -156,21 +160,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -179,14 +183,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -208,31 +213,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -253,21 +259,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -276,14 +282,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition prev_randao : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the `prev_randao` value onto the stack.
 
@@ -304,21 +311,21 @@ Definition prev_randao : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "prev_randao" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "prev_randao" |)
         ],
         make_dict []
       |)
@@ -327,14 +334,15 @@ Definition prev_randao : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -355,21 +363,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -378,14 +386,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -403,21 +412,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -426,7 +435,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/comparison.v b/CoqOfPython/ethereum/paris/vm/instructions/comparison.v
index f0bbc4a..6a1ee53 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/control_flow.v b/CoqOfPython/ethereum/paris/vm/instructions/control_flow.v
index 077810e..d3d5774 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/environment.v b/CoqOfPython/ethereum/paris/vm/instructions/environment.v
index 44987c3..fddea67 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,42 +1472,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1500,21 +1520,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1523,7 +1543,7 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/keccak.v b/CoqOfPython/ethereum/paris/vm/instructions/keccak.v
index e935544..03d7f72 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/log.v b/CoqOfPython/ethereum/paris/vm/instructions/log.v
index e38fab2..025ff79 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_paris_vm_stack_imports_pop :
   IsImported globals "ethereum.paris.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/memory.v b/CoqOfPython/ethereum/paris/vm/instructions/memory.v
index 211fafb..d54e1e1 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/proofs/arithmetic.v b/CoqOfPython/ethereum/paris/vm/instructions/proofs/arithmetic.v
new file mode 100644
index 0000000..bd9d4ee
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/instructions/proofs/arithmetic.v
@@ -0,0 +1,69 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import proofs.CoqOfPython.
+Require Import simulations.CoqOfPython.
+Require Import proofs.heap.
+
+Require ethereum.paris.vm.instructions.simulations.arithmetic.
+Require ethereum.paris.vm.instructions.arithmetic.
+
+Require ethereum.simulations.base_types.
+Module U256 := base_types.U256.
+
+Import Run.
+
+Module Option.
+  Definition map {A B} (f : A -> B) (x : option A) : option B :=
+    match x with
+    | Some x => Some (f x)
+    | None => None
+    end.
+End Option.
+
+Module AddLocals.
+  Record t : Set := {
+    x : option U256.t;
+    y : option U256.t;
+    result : option U256.t;
+  }.
+
+  Definition init : t :=
+    {|
+      x := None;
+      y := None;
+      result := None;
+    |}.
+
+  Definition to_object (locals : t) : Object.t Value.t :=
+    Object.make [
+      ("x", Option.map U256.to_value locals.(x));
+      ("y", Option.map U256.to_value locals.(y));
+      ("result", Option.map U256.to_value locals.(result))
+    ].
+End AddLocals.
+
+Lemma run_add (stack : Stack.t) (heap : Heap.t) :
+  let '(result, evm') := simulations.arithmetic.add heap.(Heap.evm) in
+  let result :=
+    match result with
+    | inl tt => inl Constant.None_
+    | inr exn => inr (Exception.Raise (Some Constant.None_))
+    end in
+  let heap' := heap <| Heap.evm := evm' |> in
+  exists fresh_stack,
+  {{ stack, heap |
+    arithmetic.add (make_list []) (make_dict []) ⇓
+    result
+  | stack ++ fresh_stack, heap' }}.
+Proof.
+  destruct simulations.arithmetic.add as [result evm'] eqn:?.
+  unfold arithmetic.add, simulations.arithmetic.add in *.
+  cbn in *.
+  eexists.
+  apply (Run.CallPrimitiveStateAllocStack AddLocals.init AddLocals.to_object); [reflexivity |].
+  cbn.
+  eapply Run.CallPrimitiveStateReadStack.
+  { now erewrite Stack.read_length_eq. }
+  { cbn.
+    admit.
+  }
+Admitted.
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/simulations/arithmetic.v b/CoqOfPython/ethereum/paris/vm/instructions/simulations/arithmetic.v
new file mode 100644
index 0000000..ad6e132
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/instructions/simulations/arithmetic.v
@@ -0,0 +1,45 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import simulations.CoqOfPython.
+Require Import simulations.builtins.
+
+Require ethereum.simulations.base_types.
+Definition U255_CEIL_VALUE := base_types.U255_CEIL_VALUE.
+Module U256 := base_types.U256.
+Definition U256_CEIL_VALUE := base_types.U256_CEIL_VALUE.
+Module Uint := base_types.Uint.
+
+Require ethereum.paris.vm.simulations.__init__.
+Module Evm := __init__.Evm.
+
+Require ethereum.paris.vm.simulations.gas.
+Definition GAS_EXPONENTIATION := gas.GAS_EXPONENTIATION.
+Definition GAS_EXPONENTIATION_PER_BYTE := gas.GAS_EXPONENTIATION_PER_BYTE.
+Definition GAS_LOW := gas.GAS_LOW.
+Definition GAS_MID := gas.GAS_MID.
+Definition GAS_VERY_LOW := gas.GAS_VERY_LOW.
+Definition charge_gas := gas.charge_gas.
+
+Require ethereum.paris.vm.simulations.stack.
+Definition pop := stack.pop.
+Definition push := stack.push.
+
+Import simulations.CoqOfPython.Notations.
+
+Definition add : MS? Evm.t Exception.t unit :=
+  (* STACK *)
+  letS? x := StateError.lift_lens Evm.Lens.stack pop in
+  letS? y := StateError.lift_lens Evm.Lens.stack pop in
+
+  (* GAS *)
+  letS? _ := charge_gas GAS_VERY_LOW in
+
+  (* OPERATION *)
+  let result := U256.wrapping_add x y in
+
+  letS? _ := StateError.lift_lens Evm.Lens.stack (push result) in
+
+  (* PROGRAM COUNTER *)
+  letS? _ := StateError.lift_lens Evm.Lens.pc (fun pc =>
+    (inl tt, Uint.__add__ pc (Uint.Make 1))) in
+
+  returnS? tt.
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/stack.v b/CoqOfPython/ethereum/paris/vm/instructions/stack.v
index 7c6a4bf..02d0f18 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_paris_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.paris.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/storage.v b/CoqOfPython/ethereum/paris/vm/instructions/storage.v
index 760b3c6..0abe74e 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/instructions/system.v b/CoqOfPython/ethereum/paris/vm/instructions/system.v
index 2ed4520..42d8e78 100644
--- a/CoqOfPython/ethereum/paris/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/paris/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.paris.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -105,28 +107,29 @@ Axiom ethereum_paris_vm_stack_imports_push :
   IsImported globals "ethereum.paris.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -136,32 +139,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -171,15 +174,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -195,10 +198,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -208,15 +211,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -237,29 +240,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -279,27 +282,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -307,10 +310,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -318,27 +321,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -351,25 +354,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -381,8 +384,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -394,9 +398,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -404,9 +408,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -414,9 +418,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -424,46 +428,46 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -472,26 +476,27 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -506,9 +511,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -516,9 +521,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -526,9 +531,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -537,9 +542,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -550,11 +555,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -564,12 +569,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -580,43 +585,43 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-            M.get_name (| globals, "call_data_words" |)
+            M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+            M.get_name (| globals, locals_stack, "call_data_words" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -625,26 +630,27 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -656,9 +662,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -666,9 +672,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -676,63 +682,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -740,24 +747,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -777,11 +784,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -789,10 +796,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -800,7 +807,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -808,10 +815,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -819,27 +826,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -852,23 +859,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -882,16 +889,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -903,14 +910,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -919,8 +926,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -932,12 +940,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -948,12 +956,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -964,9 +972,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -974,9 +982,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -984,9 +992,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -994,9 +1002,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1004,9 +1012,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1014,12 +1022,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1029,28 +1037,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1060,16 +1068,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1077,7 +1085,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1085,7 +1093,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1093,13 +1101,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1107,56 +1115,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1165,25 +1173,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1192,17 +1200,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1212,32 +1220,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1245,14 +1253,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1264,12 +1273,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1280,12 +1289,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1296,9 +1305,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1306,9 +1315,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1316,9 +1325,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1326,9 +1335,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1336,26 +1345,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1365,28 +1374,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1395,13 +1404,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1409,58 +1418,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1469,17 +1478,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1489,32 +1498,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1522,14 +1531,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1541,12 +1551,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1556,28 +1566,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1589,20 +1599,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1615,7 +1625,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1623,32 +1633,32 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1656,33 +1666,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1692,9 +1702,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1702,19 +1712,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1724,15 +1734,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1744,12 +1755,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1760,12 +1771,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1776,9 +1787,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1786,9 +1797,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1796,9 +1807,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1806,9 +1817,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1816,12 +1827,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1831,104 +1842,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1940,12 +1952,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1956,12 +1968,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1972,9 +1984,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1982,9 +1994,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1992,9 +2004,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2002,9 +2014,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2012,12 +2024,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2027,110 +2039,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2142,9 +2155,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2152,9 +2165,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2162,54 +2175,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/interpreter.v b/CoqOfPython/ethereum/paris/vm/interpreter.v
index ddfc003..57a5930 100644
--- a/CoqOfPython/ethereum/paris/vm/interpreter.v
+++ b/CoqOfPython/ethereum/paris/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.interpreter".
+Definition globals : Globals.t := "ethereum.paris.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -128,7 +130,7 @@ Axiom ethereum_paris_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -151,8 +153,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -174,9 +177,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -188,10 +191,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -199,44 +202,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -250,10 +253,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -266,10 +269,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -278,13 +281,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -294,12 +297,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -316,14 +319,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -331,7 +334,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -339,7 +342,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -351,22 +354,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -376,29 +379,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -406,8 +409,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -424,43 +428,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -468,24 +472,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -493,22 +497,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -528,13 +533,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -546,17 +551,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -564,10 +569,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -575,12 +580,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -592,10 +597,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -603,13 +608,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -617,22 +622,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -650,14 +656,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -665,13 +671,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/memory.v b/CoqOfPython/ethereum/paris/vm/memory.v
index 0a1308d..5ebc425 100644
--- a/CoqOfPython/ethereum/paris/vm/memory.v
+++ b/CoqOfPython/ethereum/paris/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.memory".
+Definition globals : Globals.t := "ethereum.paris.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/__init__.v
index 0726d50..8640d91 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/alt_bn128.v
index 21ebabe..37c3636 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_paris_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.paris.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/blake2f.v
index e4c8b13..a565bf1 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_paris_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.paris.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ecrecover.v
index 62c83c2..4ff4a3c 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_paris_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.paris.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/identity.v
index 1936c37..fec619f 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_paris_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.paris.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/mapping.v
index eb81d35..01cefc2 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/modexp.v
index 6904c05..b7ef5f2 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ripemd160.v
index 5a9416e..b5edc19 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_paris_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.paris.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/sha256.v
index 882cecd..33c4215 100644
--- a/CoqOfPython/ethereum/paris/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/paris/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.paris.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_paris_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.paris.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/paris/vm/runtime.v b/CoqOfPython/ethereum/paris/vm/runtime.v
index 4733e48..d53167e 100644
--- a/CoqOfPython/ethereum/paris/vm/runtime.v
+++ b/CoqOfPython/ethereum/paris/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.runtime".
+Definition globals : Globals.t := "ethereum.paris.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_paris_vm_instructions_imports_Ops :
   IsImported globals "ethereum.paris.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/paris/vm/simulations/__init__.v b/CoqOfPython/ethereum/paris/vm/simulations/__init__.v
new file mode 100644
index 0000000..5fb9a63
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/simulations/__init__.v
@@ -0,0 +1,109 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import simulations.CoqOfPython.
+
+Require ethereum.simulations.base_types.
+Module U64 := base_types.U64.
+Module U256 := base_types.U256.
+Module Bytes := base_types.Bytes.
+Module Bytes0 := base_types.Bytes0.
+Module Bytes32 := base_types.Bytes32.
+Module Uint := base_types.Uint.
+
+Require ethereum.crypto.simulations.hash.
+Module Hash32 := hash.Hash32.
+
+Require ethereum.paris.simulations.fork_types.
+Module Address := fork_types.Address.
+
+Require ethereum.paris.simulations.state.
+Module State := state.State.
+
+Module Environment.
+  Record t : Set := {
+    caller : Address.t;
+    block_hashes : list Hash32.t;
+    origin : Address.t;
+    coinbase : Address.t;
+    number : Uint.t;
+    base_fee_per_gas : Uint.t;
+    gas_limit : Uint.t;
+    gas_price : Uint.t;
+    time : U256.t;
+    prev_randao : Bytes32.t;
+    state : State.t;
+    chain_id : U64.t;
+    traces : list unit
+  }.
+End Environment.
+
+Module Message.
+  (** We parametrize this type by the environment. *)
+  Record t {Evm : Set} : Set := {
+    caller : Address.t;
+    target : Bytes0.t + Address.t;
+    current_target : Address.t;
+    gas : Uint.t;
+    value : U256.t;
+    data : Bytes.t;
+    code_address : option Address.t;
+    code : Bytes.t;
+    depth : Uint.t;
+    should_transfer_value : bool;
+    is_static : bool;
+    accessed_addresses : list Address.t;
+    accessed_storage_keys : list (Address.t * Bytes32.t);
+    parent_evm : option Evm
+  }.
+  Arguments t : clear implicits.
+End Message.
+
+Module Evm.
+  (** We split the record as it is recursive in the [message] field, and we cannot have recursive
+      records. *)
+  Module Rest.
+    Record t : Set := {
+      pc : Uint.t;
+      stack : list (U256.t);
+      memory : list ascii;
+      code : Bytes.t;
+      gas_left : Uint.t;
+      env : Environment.t;
+      valid_jump_destinations : list Uint.t;
+      logs : list unit;
+      refund_counter : Z;
+      running : bool;
+      output : Bytes.t;
+      accounts_to_delete : list Address.t;
+      touched_accounts : list Address.t;
+      return_data : Bytes.t;
+      error : option Exception.t;
+      accessed_addresses : list Address.t;
+      accessed_storage_keys : list (Address.t * Bytes32.t)
+    }.
+  End Rest.
+
+  Inductive t : Set :=
+  | Make (message : Message.t t) (rest : Rest.t).
+
+  Module Lens.
+    Definition message : Lens.t t (Message.t t) := {|
+      Lens.read '(Make message _) := message;
+      Lens.write '(Make _ rest) message := Make message rest;
+    |}.
+
+    Definition pc : Lens.t t Uint.t := {|
+      Lens.read '(Make _ rest) := rest.(Rest.pc);
+      Lens.write '(Make message rest) pc := Make message rest<|Rest.pc := pc|>;
+    |}.
+
+    Definition stack : Lens.t t (list U256.t) := {|
+      Lens.read '(Make _ rest) := rest.(Rest.stack);
+      Lens.write '(Make message rest) stack := Make message rest<|Rest.stack := stack|>;
+    |}.
+
+    Definition memory : Lens.t t (list ascii) := {|
+      Lens.read '(Make _ rest) := rest.(Rest.memory);
+      Lens.write '(Make message rest) memory := Make message rest<|Rest.memory := memory|>;
+    |}.
+  End Lens.
+End Evm.
diff --git a/CoqOfPython/ethereum/paris/vm/simulations/exceptions.v b/CoqOfPython/ethereum/paris/vm/simulations/exceptions.v
new file mode 100644
index 0000000..db4fc89
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/simulations/exceptions.v
@@ -0,0 +1,20 @@
+Require Import CoqOfPython.CoqOfPython.
+
+Module ExceptionalHalt.
+  Inductive t : Set :=
+  | StackUnderflowError
+  | StackOverflowError
+  | OutOfGasError
+  | InvalidOpcode (code : Z)
+  | InvalidJumpDestError
+  | StackDepthLimitError
+  | WriteInStaticContext
+  | OutOfBoundsRead
+  | InvalidParameter
+  | InvalidContractPrefix
+  | AddressCollision.
+End ExceptionalHalt.
+
+Module Revert.
+  Inductive t : Set :=.
+End Revert.
diff --git a/CoqOfPython/ethereum/paris/vm/simulations/gas.v b/CoqOfPython/ethereum/paris/vm/simulations/gas.v
new file mode 100644
index 0000000..7cfb7ce
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/simulations/gas.v
@@ -0,0 +1,55 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import simulations.CoqOfPython.
+Require Import simulations.builtins.
+
+Require ethereum.simulations.base_types.
+Module U256 := base_types.U256.
+Module Uint := base_types.Uint.
+
+Require ethereum.paris.vm.simulations.__init__.
+Module Evm := __init__.Evm.
+
+Import simulations.CoqOfPython.Notations.
+
+Definition GAS_JUMPDEST := Uint.Make 1.
+Definition GAS_BASE := Uint.Make 2.
+Definition GAS_VERY_LOW := Uint.Make 3.
+Definition GAS_STORAGE_SET := Uint.Make 20000.
+Definition GAS_STORAGE_UPDATE := Uint.Make 5000.
+Definition GAS_STORAGE_CLEAR_REFUND := Uint.Make 4800.
+Definition GAS_LOW := Uint.Make 5.
+Definition GAS_MID := Uint.Make 8.
+Definition GAS_HIGH := Uint.Make 10.
+Definition GAS_EXPONENTIATION := Uint.Make 10.
+Definition GAS_EXPONENTIATION_PER_BYTE := Uint.Make 50.
+Definition GAS_MEMORY := Uint.Make 3.
+Definition GAS_KECCAK256 := Uint.Make 30.
+Definition GAS_KECCAK256_WORD := Uint.Make 6.
+Definition GAS_COPY := Uint.Make 3.
+Definition GAS_BLOCK_HASH := Uint.Make 20.
+Definition GAS_LOG := Uint.Make 375.
+Definition GAS_LOG_DATA := Uint.Make 8.
+Definition GAS_LOG_TOPIC := Uint.Make 375.
+Definition GAS_CREATE := Uint.Make 32000.
+Definition GAS_CODE_DEPOSIT := Uint.Make 200.
+Definition GAS_ZERO := Uint.Make 0.
+Definition GAS_NEW_ACCOUNT := Uint.Make 25000.
+Definition GAS_CALL_VALUE := Uint.Make 9000.
+Definition GAS_CALL_STIPEND := Uint.Make 2300.
+Definition GAS_SELF_DESTRUCT := Uint.Make 5000.
+Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT := Uint.Make 25000.
+Definition GAS_ECRECOVER := Uint.Make 3000.
+Definition GAS_SHA256 := Uint.Make 60.
+Definition GAS_SHA256_WORD := Uint.Make 12.
+Definition GAS_RIPEMD160 := Uint.Make 600.
+Definition GAS_RIPEMD160_WORD := Uint.Make 120.
+Definition GAS_IDENTITY := Uint.Make 15.
+Definition GAS_IDENTITY_WORD := Uint.Make 3.
+Definition GAS_RETURN_DATA_COPY := Uint.Make 3.
+Definition GAS_FAST_STEP := Uint.Make 5.
+Definition GAS_BLAKE2_PER_ROUND := Uint.Make 1.
+Definition GAS_COLD_SLOAD := Uint.Make 2100.
+Definition GAS_COLD_ACCOUNT_ACCESS := Uint.Make 2600.
+Definition GAS_WARM_ACCESS := Uint.Make 100.
+
+Parameter charge_gas : forall (amount : Uint.t), MS? Evm.t Exception.t unit.
diff --git a/CoqOfPython/ethereum/paris/vm/simulations/stack.v b/CoqOfPython/ethereum/paris/vm/simulations/stack.v
new file mode 100644
index 0000000..e50f7a7
--- /dev/null
+++ b/CoqOfPython/ethereum/paris/vm/simulations/stack.v
@@ -0,0 +1,35 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import simulations.CoqOfPython.
+Require Import simulations.builtins.
+
+Require Import simulations.base_types.
+Module U256 := base_types.U256.
+
+Import simulations.CoqOfPython.Notations.
+
+Definition pop : MS? (list U256.t) Exception.t U256.t :=
+  fun stack =>
+    match stack with
+    | [] =>
+      (
+        inr (Exception.EthereumException (
+          exceptions.EthereumException.ExceptionalHalt
+            exceptions.ExceptionalHalt.StackUnderflowError
+        )),
+        stack
+      )
+    | x :: rest => (inl x, rest)
+    end.
+
+Definition push (value : U256.t) : MS? (list U256.t) Exception.t unit :=
+  fun stack =>
+    if Z.of_nat (List.length stack) =? 1024 then
+      (
+        inr (Exception.EthereumException (
+          exceptions.EthereumException.ExceptionalHalt
+            exceptions.ExceptionalHalt.StackOverflowError
+        )),
+        stack
+      )
+    else
+      (inl tt, value :: stack).
diff --git a/CoqOfPython/ethereum/paris/vm/stack.v b/CoqOfPython/ethereum/paris/vm/stack.v
index 026c5b4..fc25118 100644
--- a/CoqOfPython/ethereum/paris/vm/stack.v
+++ b/CoqOfPython/ethereum/paris/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.paris.vm.stack".
+Definition globals : Globals.t := "ethereum.paris.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_paris_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.paris.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/rlp.v b/CoqOfPython/ethereum/rlp.v
index d513852..3a9bf15 100644
--- a/CoqOfPython/ethereum/rlp.v
+++ b/CoqOfPython/ethereum/rlp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.rlp".
+Definition globals : Globals.t := "ethereum.rlp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -70,12 +72,13 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition RLP : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Any" |)
+  M.get_name (| globals, locals_stack, "Any" |)
 )).
 
 Definition encode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes `raw_data` into a sequence of bytes using RLP.
 
@@ -94,10 +97,10 @@ Definition encode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "raw_data" |);
-            make_tuple [ M.get_name (| globals, "bytearray" |); M.get_name (| globals, "bytes" |) ]
+            M.get_name (| globals, locals_stack, "raw_data" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "bytearray" |); M.get_name (| globals, locals_stack, "bytes" |) ]
           ],
           make_dict []
         |),
@@ -105,9 +108,9 @@ Definition encode : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_bytes" |),
+            M.get_name (| globals, locals_stack, "encode_bytes" |),
             make_list [
-              M.get_name (| globals, "raw_data" |)
+              M.get_name (| globals, locals_stack, "raw_data" |)
             ],
             make_dict []
           |)
@@ -119,10 +122,10 @@ Definition encode : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "raw_data" |);
-                make_tuple [ M.get_name (| globals, "Uint" |); M.get_name (| globals, "FixedUint" |) ]
+                M.get_name (| globals, locals_stack, "raw_data" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "FixedUint" |) ]
               ],
               make_dict []
             |),
@@ -130,10 +133,10 @@ Definition encode : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "encode" |),
+                M.get_name (| globals, locals_stack, "encode" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "raw_data" |), "to_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "raw_data" |), "to_be_bytes" |),
                     make_list [],
                     make_dict []
                   |)
@@ -148,10 +151,10 @@ Definition encode : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "raw_data" |);
-                    M.get_name (| globals, "str" |)
+                    M.get_name (| globals, locals_stack, "raw_data" |);
+                    M.get_name (| globals, locals_stack, "str" |)
                   ],
                   make_dict []
                 |),
@@ -159,10 +162,10 @@ Definition encode : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_name (| globals, "encode_bytes" |),
+                    M.get_name (| globals, locals_stack, "encode_bytes" |),
                     make_list [
                       M.call (|
-                        M.get_field (| M.get_name (| globals, "raw_data" |), "encode" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "raw_data" |), "encode" |),
                         make_list [],
                         make_dict []
                       |)
@@ -177,10 +180,10 @@ Definition encode : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "raw_data" |);
-                        M.get_name (| globals, "bool" |)
+                        M.get_name (| globals, locals_stack, "raw_data" |);
+                        M.get_name (| globals, locals_stack, "bool" |)
                       ],
                       make_dict []
                     |),
@@ -189,12 +192,12 @@ Definition encode : Value.t -> Value.t -> M :=
                     let _ :=
                       (* if *)
                       M.if_then_else (|
-                        M.get_name (| globals, "raw_data" |),
+                        M.get_name (| globals, locals_stack, "raw_data" |),
                       (* then *)
                       ltac:(M.monadic (
                         let _ := M.return_ (|
                           M.call (|
-                            M.get_name (| globals, "encode_bytes" |),
+                            M.get_name (| globals, locals_stack, "encode_bytes" |),
                             make_list [
                               Constant.bytes "01"
                             ],
@@ -206,7 +209,7 @@ Definition encode : Value.t -> Value.t -> M :=
                       )), ltac:(M.monadic (
                         let _ := M.return_ (|
                           M.call (|
-                            M.get_name (| globals, "encode_bytes" |),
+                            M.get_name (| globals, locals_stack, "encode_bytes" |),
                             make_list [
                               Constant.bytes ""
                             ],
@@ -222,10 +225,10 @@ Definition encode : Value.t -> Value.t -> M :=
                       (* if *)
                       M.if_then_else (|
                         M.call (|
-                          M.get_name (| globals, "isinstance" |),
+                          M.get_name (| globals, locals_stack, "isinstance" |),
                           make_list [
-                            M.get_name (| globals, "raw_data" |);
-                            M.get_name (| globals, "Sequence" |)
+                            M.get_name (| globals, locals_stack, "raw_data" |);
+                            M.get_name (| globals, locals_stack, "Sequence" |)
                           ],
                           make_dict []
                         |),
@@ -233,9 +236,9 @@ Definition encode : Value.t -> Value.t -> M :=
                       ltac:(M.monadic (
                         let _ := M.return_ (|
                           M.call (|
-                            M.get_name (| globals, "encode_sequence" |),
+                            M.get_name (| globals, locals_stack, "encode_sequence" |),
                             make_list [
-                              M.get_name (| globals, "raw_data" |)
+                              M.get_name (| globals, locals_stack, "raw_data" |)
                             ],
                             make_dict []
                           |)
@@ -247,9 +250,9 @@ Definition encode : Value.t -> Value.t -> M :=
                           (* if *)
                           M.if_then_else (|
                             M.call (|
-                              M.get_name (| globals, "is_dataclass" |),
+                              M.get_name (| globals, locals_stack, "is_dataclass" |),
                               make_list [
-                                M.get_name (| globals, "raw_data" |)
+                                M.get_name (| globals, locals_stack, "raw_data" |)
                               ],
                               make_dict []
                             |),
@@ -257,12 +260,12 @@ Definition encode : Value.t -> Value.t -> M :=
                           ltac:(M.monadic (
                             let _ := M.return_ (|
                               M.call (|
-                                M.get_name (| globals, "encode" |),
+                                M.get_name (| globals, locals_stack, "encode" |),
                                 make_list [
                                   M.call (|
-                                    M.get_name (| globals, "astuple" |),
+                                    M.get_name (| globals, locals_stack, "astuple" |),
                                     make_list [
-                                      M.get_name (| globals, "raw_data" |)
+                                      M.get_name (| globals, locals_stack, "raw_data" |)
                                     ],
                                     make_dict []
                                   |)
@@ -274,15 +277,15 @@ Definition encode : Value.t -> Value.t -> M :=
                           (* else *)
                           )), ltac:(M.monadic (
                             let _ := M.raise (| Some (M.call (|
-                              M.get_name (| globals, "RLPEncodingError" |),
+                              M.get_name (| globals, locals_stack, "RLPEncodingError" |),
                               make_list [
                                 M.call (|
                                   M.get_field (| Constant.str "RLP Encoding of type {} is not supported", "format" |),
                                   make_list [
                                     M.call (|
-                                      M.get_name (| globals, "type" |),
+                                      M.get_name (| globals, locals_stack, "type" |),
                                       make_list [
-                                        M.get_name (| globals, "raw_data" |)
+                                        M.get_name (| globals, locals_stack, "raw_data" |)
                                       ],
                                       make_dict []
                                     |)
@@ -307,8 +310,9 @@ Definition encode : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes `raw_bytes`, a sequence of bytes, using RLP.
 
@@ -325,12 +329,12 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "len_raw_data" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "raw_bytes" |)
+              M.get_name (| globals, locals_stack, "raw_bytes" |)
             ],
             make_dict []
           |)
@@ -343,13 +347,13 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "len_raw_data" |),
+            M.get_name (| globals, locals_stack, "len_raw_data" |),
             Constant.int 1
           |),
           ltac:(M.monadic (
             Compare.lt (|
               M.get_subscript (|
-                M.get_name (| globals, "raw_bytes" |),
+                M.get_name (| globals, locals_stack, "raw_bytes" |),
                 Constant.int 0
               |),
               Constant.int 128
@@ -359,7 +363,7 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "raw_bytes" |)
+          M.get_name (| globals, locals_stack, "raw_bytes" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -368,7 +372,7 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt (|
-              M.get_name (| globals, "len_raw_data" |),
+              M.get_name (| globals, locals_stack, "len_raw_data" |),
               Constant.int 56
             |),
           (* then *)
@@ -376,18 +380,18 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
             let _ := M.return_ (|
               BinOp.add (|
                 M.call (|
-                  M.get_name (| globals, "bytes" |),
+                  M.get_name (| globals, locals_stack, "bytes" |),
                   make_list [
                     make_list [
                       BinOp.add (|
                         Constant.int 128,
-                        M.get_name (| globals, "len_raw_data" |)
+                        M.get_name (| globals, locals_stack, "len_raw_data" |)
                       |)
                     ]
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "raw_bytes" |)
+                M.get_name (| globals, locals_stack, "raw_bytes" |)
               |)
             |) in
             M.pure Constant.None_
@@ -396,7 +400,7 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "len_raw_data_as_be" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "len_raw_data" |), "to_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "len_raw_data" |), "to_be_bytes" |),
                 make_list [],
                 make_dict []
               |)
@@ -405,15 +409,15 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
               BinOp.add (|
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "bytes" |),
+                    M.get_name (| globals, locals_stack, "bytes" |),
                     make_list [
                       make_list [
                         BinOp.add (|
                           Constant.int 183,
                           M.call (|
-                            M.get_name (| globals, "len" |),
+                            M.get_name (| globals, locals_stack, "len" |),
                             make_list [
-                              M.get_name (| globals, "len_raw_data_as_be" |)
+                              M.get_name (| globals, locals_stack, "len_raw_data_as_be" |)
                             ],
                             make_dict []
                           |)
@@ -422,9 +426,9 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
                     ],
                     make_dict []
                   |),
-                  M.get_name (| globals, "len_raw_data_as_be" |)
+                  M.get_name (| globals, locals_stack, "len_raw_data_as_be" |)
                 |),
-                M.get_name (| globals, "raw_bytes" |)
+                M.get_name (| globals, locals_stack, "raw_bytes" |)
               |)
             |) in
             M.pure Constant.None_
@@ -434,8 +438,9 @@ Definition encode_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_sequence : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_sequence" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_sequence" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a list of RLP encodable objects (`raw_sequence`) using RLP.
 
@@ -452,9 +457,9 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "joined_encodings" ,
       M.call (|
-        M.get_name (| globals, "get_joined_encodings" |),
+        M.get_name (| globals, locals_stack, "get_joined_encodings" |),
         make_list [
-          M.get_name (| globals, "raw_sequence" |)
+          M.get_name (| globals, locals_stack, "raw_sequence" |)
         ],
         make_dict []
       |)
@@ -462,12 +467,12 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "len_joined_encodings" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "joined_encodings" |)
+              M.get_name (| globals, locals_stack, "joined_encodings" |)
             ],
             make_dict []
           |)
@@ -479,7 +484,7 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "len_joined_encodings" |),
+          M.get_name (| globals, locals_stack, "len_joined_encodings" |),
           Constant.int 56
         |),
       (* then *)
@@ -487,18 +492,18 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           BinOp.add (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 make_list [
                   BinOp.add (|
                     Constant.int 192,
-                    M.get_name (| globals, "len_joined_encodings" |)
+                    M.get_name (| globals, locals_stack, "len_joined_encodings" |)
                   |)
                 ]
               ],
               make_dict []
             |),
-            M.get_name (| globals, "joined_encodings" |)
+            M.get_name (| globals, locals_stack, "joined_encodings" |)
           |)
         |) in
         M.pure Constant.None_
@@ -507,7 +512,7 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "len_joined_encodings_as_be" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "len_joined_encodings" |), "to_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "len_joined_encodings" |), "to_be_bytes" |),
             make_list [],
             make_dict []
           |)
@@ -516,15 +521,15 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Bytes" |),
+                M.get_name (| globals, locals_stack, "Bytes" |),
                 make_list [
                   make_list [
                     BinOp.add (|
                       Constant.int 247,
                       M.call (|
-                        M.get_name (| globals, "len" |),
+                        M.get_name (| globals, locals_stack, "len" |),
                         make_list [
-                          M.get_name (| globals, "len_joined_encodings_as_be" |)
+                          M.get_name (| globals, locals_stack, "len_joined_encodings_as_be" |)
                         ],
                         make_dict []
                       |)
@@ -533,9 +538,9 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
                 ],
                 make_dict []
               |),
-              M.get_name (| globals, "len_joined_encodings_as_be" |)
+              M.get_name (| globals, locals_stack, "len_joined_encodings_as_be" |)
             |),
-            M.get_name (| globals, "joined_encodings" |)
+            M.get_name (| globals, locals_stack, "joined_encodings" |)
           |)
         |) in
         M.pure Constant.None_
@@ -543,8 +548,9 @@ Definition encode_sequence : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_joined_encodings : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_sequence" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_sequence" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain concatenation of rlp encoding for each item in the sequence
     raw_sequence.
@@ -572,8 +578,9 @@ Definition get_joined_encodings : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "encoded_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "encoded_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decodes an integer, byte sequence, or list of RLP encodable objects
     from the byte sequence `encoded_data`, using RLP.
@@ -589,20 +596,20 @@ Definition decode : Value.t -> Value.t -> M :=
         Object decoded from `encoded_data`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_data" |)
+            M.get_name (| globals, locals_stack, "encoded_data" |)
           ],
           make_dict []
         |),
         Constant.int 0
       |);
       M.call (|
-        M.get_name (| globals, "RLPDecodingError" |),
+        M.get_name (| globals, locals_stack, "RLPDecodingError" |),
         make_list [
           Constant.str "Cannot decode empty bytestring"
         ],
@@ -616,7 +623,7 @@ Definition decode : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt_e (|
           M.get_subscript (|
-            M.get_name (| globals, "encoded_data" |),
+            M.get_name (| globals, locals_stack, "encoded_data" |),
             Constant.int 0
           |),
           Constant.int 191
@@ -625,9 +632,9 @@ Definition decode : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "decode_to_bytes" |),
+            M.get_name (| globals, locals_stack, "decode_to_bytes" |),
             make_list [
-              M.get_name (| globals, "encoded_data" |)
+              M.get_name (| globals, locals_stack, "encoded_data" |)
             ],
             make_dict []
           |)
@@ -637,9 +644,9 @@ Definition decode : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "decode_to_sequence" |),
+            M.get_name (| globals, locals_stack, "decode_to_sequence" |),
             make_list [
-              M.get_name (| globals, "encoded_data" |)
+              M.get_name (| globals, locals_stack, "encoded_data" |)
             ],
             make_dict []
           |)
@@ -650,7 +657,7 @@ Definition decode : Value.t -> Value.t -> M :=
 
 Definition T : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "T"
     ],
@@ -659,8 +666,9 @@ Definition T : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition decode_to : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "cls"; "encoded_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "encoded_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode the bytes in `encoded_data` to an object of type `cls`. `cls` can be
     a `Bytes` subclass, a dataclass, `Uint`, `U256` or `Tuple[cls]`.
@@ -679,13 +687,13 @@ Definition decode_to : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "_decode_to" |),
+        M.get_name (| globals, locals_stack, "_decode_to" |),
         make_list [
-          M.get_name (| globals, "cls" |);
+          M.get_name (| globals, locals_stack, "cls" |);
           M.call (|
-            M.get_name (| globals, "decode" |),
+            M.get_name (| globals, locals_stack, "decode" |),
             make_list [
-              M.get_name (| globals, "encoded_data" |)
+              M.get_name (| globals, locals_stack, "encoded_data" |)
             ],
             make_dict []
           |)
@@ -696,8 +704,9 @@ Definition decode_to : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _decode_to : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "cls"; "raw_rlp" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "cls"; "raw_rlp" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode the rlp structure in `encoded_data` to an object of type `cls`.
     `cls` can be a `Bytes` subclass, a dataclass, `Uint`, `U256`,
@@ -720,15 +729,15 @@ Definition _decode_to : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           M.call (|
-            M.get_name (| globals, "isinstance" |),
+            M.get_name (| globals, locals_stack, "isinstance" |),
             make_list [
-              M.get_name (| globals, "cls" |);
+              M.get_name (| globals, locals_stack, "cls" |);
               M.call (|
-                M.get_name (| globals, "type" |),
+                M.get_name (| globals, locals_stack, "type" |),
                 make_list [
                   M.get_subscript (|
-                    M.get_name (| globals, "Tuple" |),
-                    make_tuple [ M.get_name (| globals, "Uint" |); Constant.ellipsis ]
+                    M.get_name (| globals, locals_stack, "Tuple" |),
+                    make_tuple [ M.get_name (| globals, locals_stack, "Uint" |); Constant.ellipsis ]
                   |)
                 ],
                 make_dict []
@@ -738,7 +747,7 @@ Definition _decode_to : Value.t -> Value.t -> M :=
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "cls" |), "_name" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "_name" |),
               Constant.str "Tuple"
             |)
           ))
@@ -746,17 +755,17 @@ Definition _decode_to : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "list" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "list" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
@@ -765,7 +774,7 @@ Definition _decode_to : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
                 Constant.int 1
               |),
               Constant.ellipsis
@@ -778,20 +787,20 @@ Definition _decode_to : Value.t -> Value.t -> M :=
             |) in
             let _ :=
               M.for_ (|
-                M.get_name (| globals, "raw_item" |),
-                M.get_name (| globals, "raw_rlp" |),
+                M.get_name (| globals, locals_stack, "raw_item" |),
+                M.get_name (| globals, locals_stack, "raw_rlp" |),
                 ltac:(M.monadic (
                   let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "args" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "args" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "_decode_to" |),
+        M.get_name (| globals, locals_stack, "_decode_to" |),
         make_list [
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
             Constant.int 0
           |);
-          M.get_name (| globals, "raw_item" |)
+          M.get_name (| globals, locals_stack, "raw_item" |)
         ],
         make_dict []
       |)
@@ -806,9 +815,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
             |) in
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "tuple" |),
+                M.get_name (| globals, locals_stack, "tuple" |),
                 make_list [
-                  M.get_name (| globals, "args" |)
+                  M.get_name (| globals, locals_stack, "args" |)
                 ],
                 make_dict []
               |)
@@ -821,48 +830,48 @@ Definition _decode_to : Value.t -> Value.t -> M :=
               make_list []
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "raw_rlp" |)
+            M.get_name (| globals, locals_stack, "raw_rlp" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "cls" |), "__args__" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ :=
               M.for_ (|
-                make_tuple [ M.get_name (| globals, "t" |); M.get_name (| globals, "raw_item" |) ],
+                make_tuple [ M.get_name (| globals, locals_stack, "t" |); M.get_name (| globals, locals_stack, "raw_item" |) ],
                 M.call (|
-      M.get_name (| globals, "zip" |),
+      M.get_name (| globals, locals_stack, "zip" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "cls" |), "__args__" |);
-        M.get_name (| globals, "raw_rlp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |);
+        M.get_name (| globals, locals_stack, "raw_rlp" |)
       ],
       make_dict []
     |),
                 ltac:(M.monadic (
                   let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "args" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "args" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "_decode_to" |),
+        M.get_name (| globals, locals_stack, "_decode_to" |),
         make_list [
-          M.get_name (| globals, "t" |);
-          M.get_name (| globals, "raw_item" |)
+          M.get_name (| globals, locals_stack, "t" |);
+          M.get_name (| globals, locals_stack, "raw_item" |)
         ],
         make_dict []
       |)
@@ -877,9 +886,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
             |) in
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "tuple" |),
+                M.get_name (| globals, locals_stack, "tuple" |),
                 make_list [
-                  M.get_name (| globals, "args" |)
+                  M.get_name (| globals, locals_stack, "args" |)
                 ],
                 make_dict []
               |)
@@ -893,26 +902,26 @@ Definition _decode_to : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "cls" |),
+              M.get_name (| globals, locals_stack, "cls" |),
               M.get_subscript (|
-                M.get_name (| globals, "Union" |),
-                make_tuple [ M.get_name (| globals, "Bytes0" |); M.get_name (| globals, "Bytes20" |) ]
+                M.get_name (| globals, locals_stack, "Union" |),
+                make_tuple [ M.get_name (| globals, locals_stack, "Bytes0" |); M.get_name (| globals, locals_stack, "Bytes20" |) ]
               |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "Bytes" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "Bytes" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
@@ -921,9 +930,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "raw_rlp" |)
+                      M.get_name (| globals, locals_stack, "raw_rlp" |)
                     ],
                     make_dict []
                   |),
@@ -933,7 +942,7 @@ Definition _decode_to : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_name (| globals, "Bytes0" |),
+                    M.get_name (| globals, locals_stack, "Bytes0" |),
                     make_list [],
                     make_dict []
                   |)
@@ -946,9 +955,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                   M.if_then_else (|
                     Compare.eq (|
                       M.call (|
-                        M.get_name (| globals, "len" |),
+                        M.get_name (| globals, locals_stack, "len" |),
                         make_list [
-                          M.get_name (| globals, "raw_rlp" |)
+                          M.get_name (| globals, locals_stack, "raw_rlp" |)
                         ],
                         make_dict []
                       |),
@@ -958,9 +967,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                   ltac:(M.monadic (
                     let _ := M.return_ (|
                       M.call (|
-                        M.get_name (| globals, "Bytes20" |),
+                        M.get_name (| globals, locals_stack, "Bytes20" |),
                         make_list [
-                          M.get_name (| globals, "raw_rlp" |)
+                          M.get_name (| globals, locals_stack, "raw_rlp" |)
                         ],
                         make_dict []
                       |)
@@ -969,15 +978,15 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "RLPDecodingError" |),
+                      M.get_name (| globals, locals_stack, "RLPDecodingError" |),
                       make_list [
                         M.call (|
                           M.get_field (| Constant.str "Bytes has length {}, expected 0 or 20", "format" |),
                           make_list [
                             M.call (|
-                              M.get_name (| globals, "len" |),
+                              M.get_name (| globals, locals_stack, "len" |),
                               make_list [
-                                M.get_name (| globals, "raw_rlp" |)
+                                M.get_name (| globals, locals_stack, "raw_rlp" |)
                               ],
                               make_dict []
                             |)
@@ -999,15 +1008,15 @@ Definition _decode_to : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 BoolOp.and (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
-                      M.get_name (| globals, "cls" |);
+                      M.get_name (| globals, locals_stack, "cls" |);
                       M.call (|
-                        M.get_name (| globals, "type" |),
+                        M.get_name (| globals, locals_stack, "type" |),
                         make_list [
                           M.get_subscript (|
-                            M.get_name (| globals, "List" |),
-                            M.get_name (| globals, "Bytes" |)
+                            M.get_name (| globals, locals_stack, "List" |),
+                            M.get_name (| globals, locals_stack, "Bytes" |)
                           |)
                         ],
                         make_dict []
@@ -1017,7 +1026,7 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_field (| M.get_name (| globals, "cls" |), "_name" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "_name" |),
                       Constant.str "List"
                     |)
                   ))
@@ -1025,17 +1034,17 @@ Definition _decode_to : Value.t -> Value.t -> M :=
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "list" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "list" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
@@ -1045,20 +1054,20 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                 |) in
                 let _ :=
                   M.for_ (|
-                    M.get_name (| globals, "raw_item" |),
-                    M.get_name (| globals, "raw_rlp" |),
+                    M.get_name (| globals, locals_stack, "raw_item" |),
+                    M.get_name (| globals, locals_stack, "raw_rlp" |),
                     ltac:(M.monadic (
                       let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "items" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "items" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "_decode_to" |),
+        M.get_name (| globals, locals_stack, "_decode_to" |),
         make_list [
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
             Constant.int 0
           |);
-          M.get_name (| globals, "raw_item" |)
+          M.get_name (| globals, locals_stack, "raw_item" |)
         ],
         make_dict []
       |)
@@ -1072,7 +1081,7 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                     ))
                 |) in
                 let _ := M.return_ (|
-                  M.get_name (| globals, "items" |)
+                  M.get_name (| globals, locals_stack, "items" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -1082,17 +1091,17 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                   M.if_then_else (|
                     BoolOp.and (|
                       M.call (|
-                        M.get_name (| globals, "isinstance" |),
+                        M.get_name (| globals, locals_stack, "isinstance" |),
                         make_list [
-                          M.get_name (| globals, "cls" |);
+                          M.get_name (| globals, locals_stack, "cls" |);
                           M.call (|
-                            M.get_name (| globals, "type" |),
+                            M.get_name (| globals, locals_stack, "type" |),
                             make_list [
                               M.get_subscript (|
-                                M.get_name (| globals, "Union" |),
-                                make_tuple [ M.get_name (| globals, "Bytes" |); M.get_subscript (|
-                                  M.get_name (| globals, "List" |),
-                                  M.get_name (| globals, "Bytes" |)
+                                M.get_name (| globals, locals_stack, "Union" |),
+                                make_tuple [ M.get_name (| globals, locals_stack, "Bytes" |); M.get_subscript (|
+                                  M.get_name (| globals, locals_stack, "List" |),
+                                  M.get_name (| globals, locals_stack, "Bytes" |)
                                 |) ]
                               |)
                             ],
@@ -1103,8 +1112,8 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                       |),
                       ltac:(M.monadic (
                         Compare.eq (|
-                          M.get_field (| M.get_name (| globals, "cls" |), "__origin__" |),
-                          M.get_name (| globals, "Union" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__origin__" |),
+                          M.get_name (| globals, locals_stack, "Union" |)
                         |)
                       ))
                     |),
@@ -1116,9 +1125,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                         BoolOp.or (|
                           Compare.not_eq (|
                             M.call (|
-                              M.get_name (| globals, "len" |),
+                              M.get_name (| globals, locals_stack, "len" |),
                               make_list [
-                                M.get_field (| M.get_name (| globals, "cls" |), "__args__" |)
+                                M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |)
                               ],
                               make_dict []
                             |),
@@ -1126,20 +1135,20 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                           |),
                           ltac:(M.monadic (
                             Compare.not_in (|
-                              M.get_name (| globals, "Bytes" |),
-                              M.get_field (| M.get_name (| globals, "cls" |), "__args__" |)
+                              M.get_name (| globals, locals_stack, "Bytes" |),
+                              M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |)
                             |)
                           ))
                         |),
                       (* then *)
                       ltac:(M.monadic (
                         let _ := M.raise (| Some (M.call (|
-                          M.get_name (| globals, "RLPDecodingError" |),
+                          M.get_name (| globals, locals_stack, "RLPDecodingError" |),
                           make_list [
                             M.call (|
                               M.get_field (| Constant.str "RLP Decoding to type {} is not supported", "format" |),
                               make_list [
-                                M.get_name (| globals, "cls" |)
+                                M.get_name (| globals, locals_stack, "cls" |)
                               ],
                               make_dict []
                             |)
@@ -1155,17 +1164,17 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                       (* if *)
                       M.if_then_else (|
                         M.call (|
-                          M.get_name (| globals, "isinstance" |),
+                          M.get_name (| globals, locals_stack, "isinstance" |),
                           make_list [
-                            M.get_name (| globals, "raw_rlp" |);
-                            M.get_name (| globals, "Bytes" |)
+                            M.get_name (| globals, locals_stack, "raw_rlp" |);
+                            M.get_name (| globals, locals_stack, "Bytes" |)
                           ],
                           make_dict []
                         |),
                       (* then *)
                       ltac:(M.monadic (
                         let _ := M.return_ (|
-                          M.get_name (| globals, "raw_rlp" |)
+                          M.get_name (| globals, locals_stack, "raw_rlp" |)
                         |) in
                         M.pure Constant.None_
                       (* else *)
@@ -1175,22 +1184,22 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                           M.if_then_else (|
                             Compare.eq (|
                               M.get_subscript (|
-                                M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+                                M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
                                 Constant.int 0
                               |),
-                              M.get_name (| globals, "Bytes" |)
+                              M.get_name (| globals, locals_stack, "Bytes" |)
                             |),
                           (* then *)
                           ltac:(M.monadic (
                             let _ := M.return_ (|
                               M.call (|
-                                M.get_name (| globals, "_decode_to" |),
+                                M.get_name (| globals, locals_stack, "_decode_to" |),
                                 make_list [
                                   M.get_subscript (|
-                                    M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+                                    M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
                                     Constant.int 1
                                   |);
-                                  M.get_name (| globals, "raw_rlp" |)
+                                  M.get_name (| globals, locals_stack, "raw_rlp" |)
                                 ],
                                 make_dict []
                               |)
@@ -1200,13 +1209,13 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                           )), ltac:(M.monadic (
                             let _ := M.return_ (|
                               M.call (|
-                                M.get_name (| globals, "_decode_to" |),
+                                M.get_name (| globals, locals_stack, "_decode_to" |),
                                 make_list [
                                   M.get_subscript (|
-                                    M.get_field (| M.get_name (| globals, "cls" |), "__args__" |),
+                                    M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "__args__" |),
                                     Constant.int 0
                                   |);
-                                  M.get_name (| globals, "raw_rlp" |)
+                                  M.get_name (| globals, locals_stack, "raw_rlp" |)
                                 ],
                                 make_dict []
                               |)
@@ -1222,10 +1231,10 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                       (* if *)
                       M.if_then_else (|
                         M.call (|
-                          M.get_name (| globals, "issubclass" |),
+                          M.get_name (| globals, locals_stack, "issubclass" |),
                           make_list [
-                            M.get_name (| globals, "cls" |);
-                            M.get_name (| globals, "bool" |)
+                            M.get_name (| globals, locals_stack, "cls" |);
+                            M.get_name (| globals, locals_stack, "bool" |)
                           ],
                           make_dict []
                         |),
@@ -1235,14 +1244,14 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                           (* if *)
                           M.if_then_else (|
                             Compare.eq (|
-                              M.get_name (| globals, "raw_rlp" |),
+                              M.get_name (| globals, locals_stack, "raw_rlp" |),
                               Constant.bytes "01"
                             |),
                           (* then *)
                           ltac:(M.monadic (
                             let _ := M.return_ (|
                               M.call (|
-                                M.get_name (| globals, "cls" |),
+                                M.get_name (| globals, locals_stack, "cls" |),
                                 make_list [
                                   Constant.bool true
                                 ],
@@ -1256,14 +1265,14 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                               (* if *)
                               M.if_then_else (|
                                 Compare.eq (|
-                                  M.get_name (| globals, "raw_rlp" |),
+                                  M.get_name (| globals, locals_stack, "raw_rlp" |),
                                   Constant.bytes ""
                                 |),
                               (* then *)
                               ltac:(M.monadic (
                                 let _ := M.return_ (|
                                   M.call (|
-                                    M.get_name (| globals, "cls" |),
+                                    M.get_name (| globals, locals_stack, "cls" |),
                                     make_list [
                                       Constant.bool false
                                     ],
@@ -1274,13 +1283,13 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                               (* else *)
                               )), ltac:(M.monadic (
                                 let _ := M.raise (| Some (M.call (|
-                                  M.get_name (| globals, "TypeError" |),
+                                  M.get_name (| globals, locals_stack, "TypeError" |),
                                   make_list [
                                     M.call (|
                                       M.get_field (| Constant.str "Cannot decode {} as {}", "format" |),
                                       make_list [
-                                        M.get_name (| globals, "raw_rlp" |);
-                                        M.get_name (| globals, "cls" |)
+                                        M.get_name (| globals, locals_stack, "raw_rlp" |);
+                                        M.get_name (| globals, locals_stack, "cls" |)
                                       ],
                                       make_dict []
                                     |)
@@ -1298,52 +1307,52 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                           (* if *)
                           M.if_then_else (|
                             M.call (|
-                              M.get_name (| globals, "issubclass" |),
+                              M.get_name (| globals, locals_stack, "issubclass" |),
                               make_list [
-                                M.get_name (| globals, "cls" |);
-                                M.get_name (| globals, "FixedBytes" |)
+                                M.get_name (| globals, locals_stack, "cls" |);
+                                M.get_name (| globals, locals_stack, "FixedBytes" |)
                               ],
                               make_dict []
                             |),
                           (* then *)
                           ltac:(M.monadic (
                             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "Bytes" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "Bytes" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "raw_rlp" |)
+            M.get_name (| globals, locals_stack, "raw_rlp" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "cls" |), "LENGTH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "cls" |), "LENGTH" |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                             let _ := M.return_ (|
                               M.call (|
-                                M.get_name (| globals, "cls" |),
+                                M.get_name (| globals, locals_stack, "cls" |),
                                 make_list [
-                                  M.get_name (| globals, "raw_rlp" |)
+                                  M.get_name (| globals, locals_stack, "raw_rlp" |)
                                 ],
                                 make_dict []
                               |)
@@ -1355,32 +1364,32 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                               (* if *)
                               M.if_then_else (|
                                 M.call (|
-                                  M.get_name (| globals, "issubclass" |),
+                                  M.get_name (| globals, locals_stack, "issubclass" |),
                                   make_list [
-                                    M.get_name (| globals, "cls" |);
-                                    M.get_name (| globals, "Bytes" |)
+                                    M.get_name (| globals, locals_stack, "cls" |);
+                                    M.get_name (| globals, locals_stack, "Bytes" |)
                                   ],
                                   make_dict []
                                 |),
                               (* then *)
                               ltac:(M.monadic (
                                 let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "Bytes" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "Bytes" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                                 let _ := M.return_ (|
-                                  M.get_name (| globals, "raw_rlp" |)
+                                  M.get_name (| globals, locals_stack, "raw_rlp" |)
                                 |) in
                                 M.pure Constant.None_
                               (* else *)
@@ -1389,27 +1398,27 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                                   (* if *)
                                   M.if_then_else (|
                                     M.call (|
-                                      M.get_name (| globals, "issubclass" |),
+                                      M.get_name (| globals, locals_stack, "issubclass" |),
                                       make_list [
-                                        M.get_name (| globals, "cls" |);
-                                        make_tuple [ M.get_name (| globals, "Uint" |); M.get_name (| globals, "FixedUint" |) ]
+                                        M.get_name (| globals, locals_stack, "cls" |);
+                                        make_tuple [ M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "FixedUint" |) ]
                                       ],
                                       make_dict []
                                     |),
                                   (* then *)
                                   ltac:(M.monadic (
                                     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "Bytes" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "Bytes" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
@@ -1421,34 +1430,34 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                                       (* if *)
                                       M.if_then_else (|
                                         M.call (|
-                                          M.get_name (| globals, "is_dataclass" |),
+                                          M.get_name (| globals, locals_stack, "is_dataclass" |),
                                           make_list [
-                                            M.get_name (| globals, "cls" |)
+                                            M.get_name (| globals, locals_stack, "cls" |)
                                           ],
                                           make_dict []
                                         |),
                                       (* then *)
                                       ltac:(M.monadic (
                                         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "isinstance" |),
+        M.get_name (| globals, locals_stack, "isinstance" |),
         make_list [
-          M.get_name (| globals, "raw_rlp" |);
-          M.get_name (| globals, "list" |)
+          M.get_name (| globals, locals_stack, "raw_rlp" |);
+          M.get_name (| globals, locals_stack, "list" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                                         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "raw_rlp" |);
-      M.get_name (| globals, "list" |)
+      M.get_name (| globals, locals_stack, "raw_rlp" |);
+      M.get_name (| globals, locals_stack, "list" |)
     ],
     make_dict []
   |) |) in
@@ -1457,16 +1466,16 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                                           make_list []
                                         |) in
                                         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "fields" |),
+              M.get_name (| globals, locals_stack, "fields" |),
               make_list [
-                M.get_name (| globals, "cls" |)
+                M.get_name (| globals, locals_stack, "cls" |)
               ],
               make_dict []
             |)
@@ -1474,43 +1483,43 @@ Definition _decode_to : Value.t -> Value.t -> M :=
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "raw_rlp" |)
+            M.get_name (| globals, locals_stack, "raw_rlp" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                                         let _ :=
                                           M.for_ (|
-                                            make_tuple [ M.get_name (| globals, "field" |); M.get_name (| globals, "rlp_item" |) ],
+                                            make_tuple [ M.get_name (| globals, locals_stack, "field" |); M.get_name (| globals, locals_stack, "rlp_item" |) ],
                                             M.call (|
-      M.get_name (| globals, "zip" |),
+      M.get_name (| globals, locals_stack, "zip" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "fields" |),
+          M.get_name (| globals, locals_stack, "fields" |),
           make_list [
-            M.get_name (| globals, "cls" |)
+            M.get_name (| globals, locals_stack, "cls" |)
           ],
           make_dict []
         |);
-        M.get_name (| globals, "raw_rlp" |)
+        M.get_name (| globals, locals_stack, "raw_rlp" |)
       ],
       make_dict []
     |),
                                             ltac:(M.monadic (
                                               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "args" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "args" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "_decode_to" |),
+        M.get_name (| globals, locals_stack, "_decode_to" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "field" |), "type" |);
-          M.get_name (| globals, "rlp_item" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "field" |), "type" |);
+          M.get_name (| globals, locals_stack, "rlp_item" |)
         ],
         make_dict []
       |)
@@ -1525,12 +1534,12 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                                         |) in
                                         let _ := M.return_ (|
                                           M.call (|
-                                            M.get_name (| globals, "cast" |),
+                                            M.get_name (| globals, locals_stack, "cast" |),
                                             make_list [
-                                              M.get_name (| globals, "T" |);
+                                              M.get_name (| globals, locals_stack, "T" |);
                                               M.call (|
-                                                M.get_name (| globals, "cls" |),
-                                                M.get_name (| globals, "args" |),
+                                                M.get_name (| globals, locals_stack, "cls" |),
+                                                M.get_name (| globals, locals_stack, "args" |),
                                                 make_dict []
                                               |)
                                             ],
@@ -1541,12 +1550,12 @@ Definition _decode_to : Value.t -> Value.t -> M :=
                                       (* else *)
                                       )), ltac:(M.monadic (
                                         let _ := M.raise (| Some (M.call (|
-                                          M.get_name (| globals, "RLPDecodingError" |),
+                                          M.get_name (| globals, locals_stack, "RLPDecodingError" |),
                                           make_list [
                                             M.call (|
                                               M.get_field (| Constant.str "RLP Decoding to type {} is not supported", "format" |),
                                               make_list [
-                                                M.get_name (| globals, "cls" |)
+                                                M.get_name (| globals, locals_stack, "cls" |)
                                               ],
                                               make_dict []
                                             |)
@@ -1574,8 +1583,9 @@ Definition _decode_to : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_to_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "encoded_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "encoded_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decodes a rlp encoded byte stream assuming that the decoded data
     should be of type `bytes`.
@@ -1596,9 +1606,9 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
         BoolOp.and (|
           Compare.eq (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "encoded_bytes" |)
+                M.get_name (| globals, locals_stack, "encoded_bytes" |)
               ],
               make_dict []
             |),
@@ -1607,7 +1617,7 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             Compare.lt (|
               M.get_subscript (|
-                M.get_name (| globals, "encoded_bytes" |),
+                M.get_name (| globals, locals_stack, "encoded_bytes" |),
                 Constant.int 0
               |),
               Constant.int 128
@@ -1617,7 +1627,7 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "encoded_bytes" |)
+          M.get_name (| globals, locals_stack, "encoded_bytes" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1627,7 +1637,7 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.lt_e (|
               M.get_subscript (|
-                M.get_name (| globals, "encoded_bytes" |),
+                M.get_name (| globals, locals_stack, "encoded_bytes" |),
                 Constant.int 0
               |),
               Constant.int 183
@@ -1638,65 +1648,65 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
               "len_raw_data" ,
               BinOp.sub (|
                 M.get_subscript (|
-                  M.get_name (| globals, "encoded_bytes" |),
+                  M.get_name (| globals, locals_stack, "encoded_bytes" |),
                   Constant.int 0
                 |),
                 Constant.int 128
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "len_raw_data" |),
+        M.get_name (| globals, locals_stack, "len_raw_data" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_bytes" |)
+            M.get_name (| globals, locals_stack, "encoded_bytes" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "raw_data" ,
               M.slice (|
-                M.get_name (| globals, "encoded_bytes" |),
+                M.get_name (| globals, locals_stack, "encoded_bytes" |),
                 Constant.int 1,
                 BinOp.add (|
                   Constant.int 1,
-                  M.get_name (| globals, "len_raw_data" |)
+                  M.get_name (| globals, locals_stack, "len_raw_data" |)
                 |),
                 Constant.None_
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       UnOp.not (| BoolOp.and (|
         Compare.eq (|
-          M.get_name (| globals, "len_raw_data" |),
+          M.get_name (| globals, locals_stack, "len_raw_data" |),
           Constant.int 1
         |),
         ltac:(M.monadic (
           Compare.lt (|
             M.get_subscript (|
-              M.get_name (| globals, "raw_data" |),
+              M.get_name (| globals, locals_stack, "raw_data" |),
               Constant.int 0
             |),
             Constant.int 128
           |)
         ))
       |) |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.return_ (|
-              M.get_name (| globals, "raw_data" |)
+              M.get_name (| globals, locals_stack, "raw_data" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -1707,7 +1717,7 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
                 BinOp.add (|
                   Constant.int 1,
                   M.get_subscript (|
-                    M.get_name (| globals, "encoded_bytes" |),
+                    M.get_name (| globals, locals_stack, "encoded_bytes" |),
                     Constant.int 0
                   |)
                 |),
@@ -1715,48 +1725,48 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
         BinOp.sub (|
-          M.get_name (| globals, "decoded_data_start_idx" |),
+          M.get_name (| globals, locals_stack, "decoded_data_start_idx" |),
           Constant.int 1
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_bytes" |)
+            M.get_name (| globals, locals_stack, "encoded_bytes" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
         M.get_subscript (|
-          M.get_name (| globals, "encoded_bytes" |),
+          M.get_name (| globals, locals_stack, "encoded_bytes" |),
           Constant.int 1
         |),
         Constant.int 0
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "len_decoded_data" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "encoded_bytes" |),
+                    M.get_name (| globals, locals_stack, "encoded_bytes" |),
                     Constant.int 1,
-                    M.get_name (| globals, "decoded_data_start_idx" |),
+                    M.get_name (| globals, locals_stack, "decoded_data_start_idx" |),
                     Constant.None_
                   |)
                 ],
@@ -1764,48 +1774,48 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_name (| globals, "len_decoded_data" |),
+        M.get_name (| globals, locals_stack, "len_decoded_data" |),
         Constant.int 56
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "decoded_data_end_idx" ,
               BinOp.add (|
-                M.get_name (| globals, "decoded_data_start_idx" |),
-                M.get_name (| globals, "len_decoded_data" |)
+                M.get_name (| globals, locals_stack, "decoded_data_start_idx" |),
+                M.get_name (| globals, locals_stack, "len_decoded_data" |)
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
         BinOp.sub (|
-          M.get_name (| globals, "decoded_data_end_idx" |),
+          M.get_name (| globals, locals_stack, "decoded_data_end_idx" |),
           Constant.int 1
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_bytes" |)
+            M.get_name (| globals, locals_stack, "encoded_bytes" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
             let _ := M.return_ (|
               M.slice (|
-                M.get_name (| globals, "encoded_bytes" |),
-                M.get_name (| globals, "decoded_data_start_idx" |),
-                M.get_name (| globals, "decoded_data_end_idx" |),
+                M.get_name (| globals, locals_stack, "encoded_bytes" |),
+                M.get_name (| globals, locals_stack, "decoded_data_start_idx" |),
+                M.get_name (| globals, locals_stack, "decoded_data_end_idx" |),
                 Constant.None_
               |)
             |) in
@@ -1816,8 +1826,9 @@ Definition decode_to_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_to_sequence : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "encoded_sequence" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "encoded_sequence" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decodes a rlp encoded byte stream assuming that the decoded data
     should be of type `Sequence` of objects.
@@ -1837,7 +1848,7 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt_e (|
           M.get_subscript (|
-            M.get_name (| globals, "encoded_sequence" |),
+            M.get_name (| globals, locals_stack, "encoded_sequence" |),
             Constant.int 0
           |),
           Constant.int 247
@@ -1848,37 +1859,37 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
           "len_joined_encodings" ,
           BinOp.sub (|
             M.get_subscript (|
-              M.get_name (| globals, "encoded_sequence" |),
+              M.get_name (| globals, locals_stack, "encoded_sequence" |),
               Constant.int 0
             |),
             Constant.int 192
           |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "len_joined_encodings" |),
+        M.get_name (| globals, locals_stack, "len_joined_encodings" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_sequence" |)
+            M.get_name (| globals, locals_stack, "encoded_sequence" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "joined_encodings" ,
           M.slice (|
-            M.get_name (| globals, "encoded_sequence" |),
+            M.get_name (| globals, locals_stack, "encoded_sequence" |),
             Constant.int 1,
             BinOp.add (|
               Constant.int 1,
-              M.get_name (| globals, "len_joined_encodings" |)
+              M.get_name (| globals, locals_stack, "len_joined_encodings" |)
             |),
             Constant.None_
           |)
@@ -1892,7 +1903,7 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
             BinOp.add (|
               Constant.int 1,
               M.get_subscript (|
-                M.get_name (| globals, "encoded_sequence" |),
+                M.get_name (| globals, locals_stack, "encoded_sequence" |),
                 Constant.int 0
               |)
             |),
@@ -1900,48 +1911,48 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
           |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
         BinOp.sub (|
-          M.get_name (| globals, "joined_encodings_start_idx" |),
+          M.get_name (| globals, locals_stack, "joined_encodings_start_idx" |),
           Constant.int 1
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_sequence" |)
+            M.get_name (| globals, locals_stack, "encoded_sequence" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
         M.get_subscript (|
-          M.get_name (| globals, "encoded_sequence" |),
+          M.get_name (| globals, locals_stack, "encoded_sequence" |),
           Constant.int 1
         |),
         Constant.int 0
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "len_joined_encodings" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "encoded_sequence" |),
+                M.get_name (| globals, locals_stack, "encoded_sequence" |),
                 Constant.int 1,
-                M.get_name (| globals, "joined_encodings_start_idx" |),
+                M.get_name (| globals, locals_stack, "joined_encodings_start_idx" |),
                 Constant.None_
               |)
             ],
@@ -1949,49 +1960,49 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
           |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_name (| globals, "len_joined_encodings" |),
+        M.get_name (| globals, locals_stack, "len_joined_encodings" |),
         Constant.int 56
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "joined_encodings_end_idx" ,
           BinOp.add (|
-            M.get_name (| globals, "joined_encodings_start_idx" |),
-            M.get_name (| globals, "len_joined_encodings" |)
+            M.get_name (| globals, locals_stack, "joined_encodings_start_idx" |),
+            M.get_name (| globals, locals_stack, "len_joined_encodings" |)
           |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
         BinOp.sub (|
-          M.get_name (| globals, "joined_encodings_end_idx" |),
+          M.get_name (| globals, locals_stack, "joined_encodings_end_idx" |),
           Constant.int 1
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_sequence" |)
+            M.get_name (| globals, locals_stack, "encoded_sequence" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "joined_encodings" ,
           M.slice (|
-            M.get_name (| globals, "encoded_sequence" |),
-            M.get_name (| globals, "joined_encodings_start_idx" |),
-            M.get_name (| globals, "joined_encodings_end_idx" |),
+            M.get_name (| globals, locals_stack, "encoded_sequence" |),
+            M.get_name (| globals, locals_stack, "joined_encodings_start_idx" |),
+            M.get_name (| globals, locals_stack, "joined_encodings_end_idx" |),
             Constant.None_
           |)
         |) in
@@ -1999,9 +2010,9 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "decode_joined_encodings" |),
+        M.get_name (| globals, locals_stack, "decode_joined_encodings" |),
         make_list [
-          M.get_name (| globals, "joined_encodings" |)
+          M.get_name (| globals, locals_stack, "joined_encodings" |)
         ],
         make_dict []
       |)
@@ -2009,8 +2020,9 @@ Definition decode_to_sequence : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_joined_encodings : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "joined_encodings" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "joined_encodings" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decodes `joined_encodings`, which is a concatenation of RLP encoded
     objects.
@@ -2036,11 +2048,11 @@ Definition decode_joined_encodings : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "item_start_idx" |),
+      M.get_name (| globals, locals_stack, "item_start_idx" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "joined_encodings" |)
+          M.get_name (| globals, locals_stack, "joined_encodings" |)
         ],
         make_dict []
       |)
@@ -2049,11 +2061,11 @@ Definition decode_joined_encodings : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "encoded_item_length" ,
             M.call (|
-              M.get_name (| globals, "decode_item_length" |),
+              M.get_name (| globals, locals_stack, "decode_item_length" |),
               make_list [
                 M.slice (|
-                  M.get_name (| globals, "joined_encodings" |),
-                  M.get_name (| globals, "item_start_idx" |),
+                  M.get_name (| globals, locals_stack, "joined_encodings" |),
+                  M.get_name (| globals, locals_stack, "item_start_idx" |),
                   Constant.None_,
                   Constant.None_
                 |)
@@ -2062,47 +2074,47 @@ Definition decode_joined_encodings : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
         BinOp.sub (|
           BinOp.add (|
-            M.get_name (| globals, "item_start_idx" |),
-            M.get_name (| globals, "encoded_item_length" |)
+            M.get_name (| globals, locals_stack, "item_start_idx" |),
+            M.get_name (| globals, locals_stack, "encoded_item_length" |)
           |),
           Constant.int 1
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "joined_encodings" |)
+            M.get_name (| globals, locals_stack, "joined_encodings" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "encoded_item" ,
             M.slice (|
-              M.get_name (| globals, "joined_encodings" |),
-              M.get_name (| globals, "item_start_idx" |),
+              M.get_name (| globals, locals_stack, "joined_encodings" |),
+              M.get_name (| globals, locals_stack, "item_start_idx" |),
               BinOp.add (|
-                M.get_name (| globals, "item_start_idx" |),
-                M.get_name (| globals, "encoded_item_length" |)
+                M.get_name (| globals, locals_stack, "item_start_idx" |),
+                M.get_name (| globals, locals_stack, "encoded_item_length" |)
               |),
               Constant.None_
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "decoded_sequence" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "decoded_sequence" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "decode" |),
+        M.get_name (| globals, locals_stack, "decode" |),
         make_list [
-          M.get_name (| globals, "encoded_item" |)
+          M.get_name (| globals, locals_stack, "encoded_item" |)
         ],
         make_dict []
       |)
@@ -2112,7 +2124,7 @@ Definition decode_joined_encodings : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.add,
             "item_start_idx",
-            M.get_name (| globals, "encoded_item_length" |)
+            M.get_name (| globals, locals_stack, "encoded_item_length" |)
           |) in
           M.pure Constant.None_
         )),
@@ -2121,13 +2133,14 @@ Definition decode_joined_encodings : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "decoded_sequence" |)
+      M.get_name (| globals, locals_stack, "decoded_sequence" |)
     |) in
     M.pure Constant.None_)).
 
 Definition decode_item_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "encoded_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "encoded_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the length of the rlp encoding for the first object in the
     encoded sequence.
@@ -2148,29 +2161,29 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
     rlp_length : `int`
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_data" |)
+            M.get_name (| globals, locals_stack, "encoded_data" |)
           ],
           make_dict []
         |),
         Constant.int 0
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "first_rlp_byte" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.get_subscript (|
-            M.get_name (| globals, "encoded_data" |),
+            M.get_name (| globals, locals_stack, "encoded_data" |),
             Constant.int 0
           |)
         ],
@@ -2180,7 +2193,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "length_length" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -2195,7 +2208,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "first_rlp_byte" |),
+          M.get_name (| globals, locals_stack, "first_rlp_byte" |),
           Constant.int 128
         |),
       (* then *)
@@ -2210,7 +2223,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "first_rlp_byte" |),
+              M.get_name (| globals, locals_stack, "first_rlp_byte" |),
               Constant.int 183
             |),
           (* then *)
@@ -2218,7 +2231,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "decoded_data_length" ,
               BinOp.sub (|
-                M.get_name (| globals, "first_rlp_byte" |),
+                M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                 Constant.int 128
               |)
             |) in
@@ -2229,7 +2242,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.lt_e (|
-                  M.get_name (| globals, "first_rlp_byte" |),
+                  M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                   Constant.int 191
                 |),
               (* then *)
@@ -2237,52 +2250,52 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "length_length" ,
                   BinOp.sub (|
-                    M.get_name (| globals, "first_rlp_byte" |),
+                    M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                     Constant.int 183
                   |)
                 |) in
                 let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "length_length" |),
+        M.get_name (| globals, locals_stack, "length_length" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_data" |)
+            M.get_name (| globals, locals_stack, "encoded_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
         M.get_subscript (|
-          M.get_name (| globals, "encoded_data" |),
+          M.get_name (| globals, locals_stack, "encoded_data" |),
           Constant.int 1
         |),
         Constant.int 0
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                 let _ := M.assign_local (|
                   "decoded_data_length" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "encoded_data" |),
+                        M.get_name (| globals, locals_stack, "encoded_data" |),
                         Constant.int 1,
                         BinOp.add (|
                           Constant.int 1,
-                          M.get_name (| globals, "length_length" |)
+                          M.get_name (| globals, locals_stack, "length_length" |)
                         |),
                         Constant.None_
                       |)
@@ -2297,7 +2310,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.lt_e (|
-                      M.get_name (| globals, "first_rlp_byte" |),
+                      M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                       Constant.int 247
                     |),
                   (* then *)
@@ -2305,7 +2318,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "decoded_data_length" ,
                       BinOp.sub (|
-                        M.get_name (| globals, "first_rlp_byte" |),
+                        M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                         Constant.int 192
                       |)
                     |) in
@@ -2316,7 +2329,7 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
                       (* if *)
                       M.if_then_else (|
                         Compare.lt_e (|
-                          M.get_name (| globals, "first_rlp_byte" |),
+                          M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                           Constant.int 255
                         |),
                       (* then *)
@@ -2324,52 +2337,52 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
                         let _ := M.assign_local (|
                           "length_length" ,
                           BinOp.sub (|
-                            M.get_name (| globals, "first_rlp_byte" |),
+                            M.get_name (| globals, locals_stack, "first_rlp_byte" |),
                             Constant.int 247
                           |)
                         |) in
                         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "length_length" |),
+        M.get_name (| globals, locals_stack, "length_length" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "encoded_data" |)
+            M.get_name (| globals, locals_stack, "encoded_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
         M.get_subscript (|
-          M.get_name (| globals, "encoded_data" |),
+          M.get_name (| globals, locals_stack, "encoded_data" |),
           Constant.int 1
         |),
         Constant.int 0
       |);
-      M.get_name (| globals, "RLPDecodingError" |)
+      M.get_name (| globals, locals_stack, "RLPDecodingError" |)
     ],
     make_dict []
   |) in
                         let _ := M.assign_local (|
                           "decoded_data_length" ,
                           M.call (|
-                            M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                            M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                             make_list [
                               M.slice (|
-                                M.get_name (| globals, "encoded_data" |),
+                                M.get_name (| globals, locals_stack, "encoded_data" |),
                                 Constant.int 1,
                                 BinOp.add (|
                                   Constant.int 1,
-                                  M.get_name (| globals, "length_length" |)
+                                  M.get_name (| globals, locals_stack, "length_length" |)
                                 |),
                                 Constant.None_
                               |)
@@ -2394,16 +2407,17 @@ Definition decode_item_length : Value.t -> Value.t -> M :=
       BinOp.add (|
         BinOp.add (|
           Constant.int 1,
-          M.get_name (| globals, "length_length" |)
+          M.get_name (| globals, locals_stack, "length_length" |)
         |),
-        M.get_name (| globals, "decoded_data_length" |)
+        M.get_name (| globals, locals_stack, "decoded_data_length" |)
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition rlp_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the keccak-256 hash of the rlp encoding of the passed in data.
 
@@ -2419,12 +2433,12 @@ Definition rlp_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "encode" |),
+            M.get_name (| globals, locals_stack, "encode" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/shanghai/__init__.v b/CoqOfPython/ethereum/shanghai/__init__.v
index c452ed3..fdd0093 100644
--- a/CoqOfPython/ethereum/shanghai/__init__.v
+++ b/CoqOfPython/ethereum/shanghai/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.__init__".
+Definition globals : Globals.t := "ethereum.shanghai.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -14,7 +16,7 @@ Axiom ethereum_fork_criteria_imports_ByTimestamp :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByTimestamp" |),
+    M.get_name (| globals, locals_stack, "ByTimestamp" |),
     make_list [
       Constant.int 1681338455
     ],
diff --git a/CoqOfPython/ethereum/shanghai/blocks.v b/CoqOfPython/ethereum/shanghai/blocks.v
index 3dccfcd..ae02dbc 100644
--- a/CoqOfPython/ethereum/shanghai/blocks.v
+++ b/CoqOfPython/ethereum/shanghai/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.blocks".
+Definition globals : Globals.t := "ethereum.shanghai.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/shanghai/bloom.v b/CoqOfPython/ethereum/shanghai/bloom.v
index f6a336d..65cd312 100644
--- a/CoqOfPython/ethereum/shanghai/bloom.v
+++ b/CoqOfPython/ethereum/shanghai/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.bloom".
+Definition globals : Globals.t := "ethereum.shanghai.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_shanghai_fork_types_imports_Bloom :
   IsImported globals "ethereum.shanghai.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/fork.v b/CoqOfPython/ethereum/shanghai/fork.v
index 1ec1953..1444e28 100644
--- a/CoqOfPython/ethereum/shanghai/fork.v
+++ b/CoqOfPython/ethereum/shanghai/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.fork".
+Definition globals : Globals.t := "ethereum.shanghai.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -164,10 +166,10 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition EMPTY_OMMER_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "keccak256" |),
+    M.get_name (| globals, locals_stack, "keccak256" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           make_list []
         ],
@@ -189,8 +191,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -210,13 +213,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -239,7 +243,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -250,9 +254,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -274,17 +278,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -297,13 +301,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -314,20 +318,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -352,125 +357,125 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "block" |), "ommers" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |),
         make_tuple [  ]
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "base_fee_per_gas" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "prev_randao" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |);
-          M.get_field (| M.get_name (| globals, "block" |), "withdrawals" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "base_fee_per_gas" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "prev_randao" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "withdrawals" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "withdrawals_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "withdrawals_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "withdrawals_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "withdrawals_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -479,9 +484,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -490,9 +495,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -506,8 +511,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_gas_limit"; "parent_gas_limit"; "parent_gas_used"; "parent_base_fee_per_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the base fee per gas for the block.
 
@@ -530,22 +536,22 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_gas_target" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "ELASTICITY_MULTIPLIER" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "ELASTICITY_MULTIPLIER" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_name (| globals, "block_gas_limit" |);
-          M.get_name (| globals, "parent_gas_limit" |)
+          M.get_name (| globals, locals_stack, "block_gas_limit" |);
+          M.get_name (| globals, locals_stack, "parent_gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -553,14 +559,14 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "parent_gas_used" |),
-          M.get_name (| globals, "parent_gas_target" |)
+          M.get_name (| globals, locals_stack, "parent_gas_used" |),
+          M.get_name (| globals, locals_stack, "parent_gas_target" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "expected_base_fee_per_gas" ,
-          M.get_name (| globals, "parent_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -569,40 +575,40 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt (|
-              M.get_name (| globals, "parent_gas_used" |),
-              M.get_name (| globals, "parent_gas_target" |)
+              M.get_name (| globals, locals_stack, "parent_gas_used" |),
+              M.get_name (| globals, locals_stack, "parent_gas_target" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_used" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_gas_used" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               M.call (|
-                M.get_name (| globals, "max" |),
+                M.get_name (| globals, locals_stack, "max" |),
                 make_list [
                   BinOp.floor_div (|
-                    M.get_name (| globals, "target_fee_gas_delta" |),
-                    M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                    M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                    M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
                   |);
                   Constant.int 1
                 ],
@@ -612,8 +618,8 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.add (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -622,36 +628,36 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "gas_used_delta" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_gas_target" |),
-                M.get_name (| globals, "parent_gas_used" |)
+                M.get_name (| globals, locals_stack, "parent_gas_target" |),
+                M.get_name (| globals, locals_stack, "parent_gas_used" |)
               |)
             |) in
             let _ := M.assign_local (|
               "parent_fee_gas_delta" ,
               BinOp.mult (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "gas_used_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "gas_used_delta" |)
               |)
             |) in
             let _ := M.assign_local (|
               "target_fee_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "parent_fee_gas_delta" |),
-                M.get_name (| globals, "parent_gas_target" |)
+                M.get_name (| globals, locals_stack, "parent_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "parent_gas_target" |)
               |)
             |) in
             let _ := M.assign_local (|
               "base_fee_per_gas_delta" ,
               BinOp.floor_div (|
-                M.get_name (| globals, "target_fee_gas_delta" |),
-                M.get_name (| globals, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
+                M.get_name (| globals, locals_stack, "target_fee_gas_delta" |),
+                M.get_name (| globals, locals_stack, "BASE_FEE_MAX_CHANGE_DENOMINATOR" |)
               |)
             |) in
             let _ := M.assign_local (|
               "expected_base_fee_per_gas" ,
               BinOp.sub (|
-                M.get_name (| globals, "parent_base_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas_delta" |)
+                M.get_name (| globals, locals_stack, "parent_base_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas_delta" |)
               |)
             |) in
             M.pure Constant.None_
@@ -660,9 +666,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "expected_base_fee_per_gas" |)
+          M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -670,8 +676,9 @@ Definition calculate_base_fee_per_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -690,124 +697,124 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |),
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "expected_base_fee_per_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_base_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_base_fee_per_gas" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_used" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_used" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "expected_base_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "header" |), "base_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "expected_base_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
         Constant.int 0
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |),
         Constant.bytes "0000000000000000"
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |),
-        M.get_name (| globals, "EMPTY_OMMER_HASH" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |),
+        M.get_name (| globals, locals_stack, "EMPTY_OMMER_HASH" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -816,21 +823,22 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "base_fee_per_gas"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -858,23 +866,23 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -883,46 +891,46 @@ Definition check_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "priority_fee_per_gas" ,
           M.call (|
-            M.get_name (| globals, "min" |),
+            M.get_name (| globals, locals_stack, "min" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |);
               BinOp.sub (|
-                M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |),
-                M.get_name (| globals, "base_fee_per_gas" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |),
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
               |)
             ],
             make_dict []
@@ -931,38 +939,39 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "effective_gas_price" ,
           BinOp.add (|
-            M.get_name (| globals, "priority_fee_per_gas" |),
-            M.get_name (| globals, "base_fee_per_gas" |)
+            M.get_name (| globals, locals_stack, "priority_fee_per_gas" |),
+            M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |),
-        M.get_name (| globals, "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |),
+        M.get_name (| globals, locals_stack, "base_fee_per_gas" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "effective_gas_price" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "error"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "error"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -986,7 +995,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
@@ -995,10 +1004,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "AccessListTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "AccessListTransaction" |)
           ],
           make_dict []
         |),
@@ -1008,9 +1017,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                M.get_name (| globals, "receipt" |)
+                M.get_name (| globals, locals_stack, "receipt" |)
               ],
               make_dict []
             |)
@@ -1023,10 +1032,10 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "FeeMarketTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
               ],
               make_dict []
             |),
@@ -1036,9 +1045,9 @@ Definition make_receipt : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "02",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "receipt" |)
+                    M.get_name (| globals, locals_stack, "receipt" |)
                   ],
                   make_dict []
                 |)
@@ -1048,7 +1057,7 @@ Definition make_receipt : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.return_ (|
-              M.get_name (| globals, "receipt" |)
+              M.get_name (| globals, locals_stack, "receipt" |)
             |) in
             M.pure Constant.None_
           )) |) in
@@ -1067,8 +1076,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id"; "withdrawals" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "base_fee_per_gas"; "block_gas_limit"; "block_time"; "prev_randao"; "transactions"; "chain_id"; "withdrawals" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -1115,7 +1125,7 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
@@ -1123,15 +1133,15 @@ Definition apply_body : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "map" |),
+          M.get_name (| globals, locals_stack, "map" |),
           make_list [
-            M.get_name (| globals, "decode_transaction" |);
-            M.get_name (| globals, "transactions" |)
+            M.get_name (| globals, locals_stack, "decode_transaction" |);
+            M.get_name (| globals, locals_stack, "transactions" |)
           ],
           make_dict []
         |)
@@ -1140,16 +1150,16 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1157,9 +1167,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_name (| globals, "encode_transaction" |),
+        M.get_name (| globals, locals_stack, "encode_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
@@ -1167,14 +1177,14 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "sender_address" |); M.get_name (| globals, "effective_gas_price" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "sender_address" |); M.get_name (| globals, locals_stack, "effective_gas_price" |) ],
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "base_fee_per_gas" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "base_fee_per_gas" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -1182,18 +1192,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |); M.get_name (| globals, "error" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |); M.get_name (| globals, locals_stack, "error" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -1201,49 +1211,49 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "error" |);
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "error" |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1254,42 +1264,42 @@ Definition apply_body : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "wd" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "wd" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "withdrawals" |)
+        M.get_name (| globals, locals_stack, "withdrawals" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "withdrawals_trie" |);
+      M.get_name (| globals, locals_stack, "withdrawals_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
@@ -1297,9 +1307,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
         make_dict []
       |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "wd" |)
+          M.get_name (| globals, locals_stack, "wd" |)
         ],
         make_dict []
       |)
@@ -1307,10 +1317,10 @@ Definition apply_body : Value.t -> Value.t -> M :=
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "process_withdrawal" |),
+    M.get_name (| globals, locals_stack, "process_withdrawal" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "wd" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "wd" |)
     ],
     make_dict []
   |) in
@@ -1318,20 +1328,20 @@ Definition apply_body : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_name (| globals, "state" |);
-                  M.get_field (| M.get_name (| globals, "wd" |), "address" |)
+                  M.get_name (| globals, locals_stack, "state" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "wd" |), "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |)
     ],
     make_dict []
   |) in
@@ -1348,35 +1358,35 @@ Definition apply_body : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "withdrawals_trie" |)
+              M.get_name (| globals, locals_stack, "withdrawals_trie" |)
             ],
             make_dict []
           |)
@@ -1387,8 +1397,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1416,30 +1427,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1448,10 +1459,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "FeeMarketTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
           ],
           make_dict []
         |),
@@ -1460,8 +1471,8 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |)
           |)
         |) in
         M.pure Constant.None_
@@ -1470,100 +1481,100 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "max_gas_fee" ,
           BinOp.mult (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "max_gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "max_gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "effective_gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "effective_gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "effective_gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "preaccessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -1571,15 +1582,15 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "preaccessed_storage_keys" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1587,10 +1598,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -1598,25 +1609,25 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
               let _ :=
                 M.for_ (|
-                  M.get_name (| globals, "key" |),
-                  M.get_name (| globals, "keys" |),
+                  M.get_name (| globals, locals_stack, "key" |),
+                  M.get_name (| globals, locals_stack, "keys" |),
                   ltac:(M.monadic (
                     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "preaccessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "preaccessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_name (| globals, "address" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "address" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
@@ -1640,14 +1651,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1655,10 +1666,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1666,20 +1677,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 5
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1688,17 +1699,17 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "priority_fee_per_gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "env" |), "gas_price" |),
-        M.get_field (| M.get_name (| globals, "env" |), "base_fee_per_gas" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "gas_price" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "env" |), "base_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1706,41 +1717,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_name (| globals, "priority_fee_per_gas" |)
+        M.get_name (| globals, locals_stack, "priority_fee_per_gas" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1748,31 +1759,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1783,20 +1794,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1809,14 +1820,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1828,27 +1839,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1864,13 +1875,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |); M.get_field (| M.get_name (| globals, "output" |), "error" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "error" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1900,13 +1912,13 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -1922,7 +1934,7 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
           BinOp.sub (|
             BinOp.pow (|
               Constant.int 2,
@@ -1946,9 +1958,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
             M.call (|
-              M.get_name (| globals, "Bytes0" |),
+              M.get_name (| globals, locals_stack, "Bytes0" |),
               make_list [
                 Constant.bytes ""
               ],
@@ -1958,15 +1970,15 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             Compare.gt (|
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "tx" |), "data" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |)
                 ],
                 make_dict []
               |),
               BinOp.mult (|
                 Constant.int 2,
-                M.get_name (| globals, "MAX_CODE_SIZE" |)
+                M.get_name (| globals, locals_stack, "MAX_CODE_SIZE" |)
               |)
             |)
           ))
@@ -1987,8 +1999,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -2017,14 +2030,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -2032,7 +2045,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -2040,7 +2053,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2054,9 +2067,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2068,20 +2081,20 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "create_cost" ,
           BinOp.add (|
-            M.get_name (| globals, "TX_CREATE_COST" |),
+            M.get_name (| globals, locals_stack, "TX_CREATE_COST" |),
             M.call (|
-              M.get_name (| globals, "int" |),
+              M.get_name (| globals, locals_stack, "int" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "init_code_cost" |),
+                  M.get_name (| globals, locals_stack, "init_code_cost" |),
                   make_list [
                     M.call (|
-                      M.get_name (| globals, "Uint" |),
+                      M.get_name (| globals, locals_stack, "Uint" |),
                       make_list [
                         M.call (|
-                          M.get_name (| globals, "len" |),
+                          M.get_name (| globals, locals_stack, "len" |),
                           make_list [
-                            M.get_field (| M.get_name (| globals, "tx" |), "data" |)
+                            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |)
                           ],
                           make_dict []
                         |)
@@ -2113,10 +2126,10 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            make_tuple [ M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+            M.get_name (| globals, locals_stack, "tx" |);
+            make_tuple [ M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
           ],
           make_dict []
         |),
@@ -2124,26 +2137,26 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ :=
           M.for_ (|
-            make_tuple [ M.get_name (| globals, "_address" |); M.get_name (| globals, "keys" |) ],
-            M.get_field (| M.get_name (| globals, "tx" |), "access_list" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "_address" |); M.get_name (| globals, locals_stack, "keys" |) ],
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |),
             ltac:(M.monadic (
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
-                M.get_name (| globals, "TX_ACCESS_LIST_ADDRESS_COST" |)
+                M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_ADDRESS_COST" |)
               |) in
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "access_list_cost",
                 BinOp.mult (|
     M.call (|
-      M.get_name (| globals, "len" |),
+      M.get_name (| globals, locals_stack, "len" |),
       make_list [
-        M.get_name (| globals, "keys" |)
+        M.get_name (| globals, locals_stack, "keys" |)
       ],
       make_dict []
     |),
-    M.get_name (| globals, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
+    M.get_name (| globals, locals_stack, "TX_ACCESS_LIST_STORAGE_KEY_COST" |)
   |)
               |) in
               M.pure Constant.None_
@@ -2159,17 +2172,17 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
               BinOp.add (|
-                M.get_name (| globals, "TX_BASE_COST" |),
-                M.get_name (| globals, "data_cost" |)
+                M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+                M.get_name (| globals, locals_stack, "data_cost" |)
               |),
-              M.get_name (| globals, "create_cost" |)
+              M.get_name (| globals, locals_stack, "create_cost" |)
             |),
-            M.get_name (| globals, "access_list_cost" |)
+            M.get_name (| globals, locals_stack, "access_list_cost" |)
           |)
         ],
         make_dict []
@@ -2178,8 +2191,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2202,47 +2216,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2250,10 +2264,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
@@ -2261,19 +2275,19 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "v" ,
-          M.get_field (| M.get_name (| globals, "tx" |), "v" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |)
         |) in
         let _ :=
           (* if *)
           M.if_then_else (|
             BoolOp.or (|
               Compare.eq (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 28
                 |)
               ))
@@ -2283,18 +2297,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
-                    M.get_name (| globals, "v" |),
+                    M.get_name (| globals, locals_stack, "v" |),
                     Constant.int 27
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_pre155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2306,58 +2320,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
                   BinOp.sub (|
                     BinOp.sub (|
-                      M.get_name (| globals, "v" |),
+                      M.get_name (| globals, locals_stack, "v" |),
                       Constant.int 35
                     |),
                     BinOp.mult (|
-                      M.get_name (| globals, "chain_id" |),
+                      M.get_name (| globals, locals_stack, "chain_id" |),
                       Constant.int 2
                     |)
                   |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_155" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_155" |),
                     make_list [
-                      M.get_name (| globals, "tx" |);
-                      M.get_name (| globals, "chain_id" |)
+                      M.get_name (| globals, locals_stack, "tx" |);
+                      M.get_name (| globals, locals_stack, "chain_id" |)
                     ],
                     make_dict []
                   |)
@@ -2374,10 +2388,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -2386,15 +2400,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "public_key" ,
               M.call (|
-                M.get_name (| globals, "secp256k1_recover" |),
+                M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                 make_list [
-                  M.get_name (| globals, "r" |);
-                  M.get_name (| globals, "s" |);
-                  M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                  M.get_name (| globals, locals_stack, "r" |);
+                  M.get_name (| globals, locals_stack, "s" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                   M.call (|
-                    M.get_name (| globals, "signing_hash_2930" |),
+                    M.get_name (| globals, locals_stack, "signing_hash_2930" |),
                     make_list [
-                      M.get_name (| globals, "tx" |)
+                      M.get_name (| globals, locals_stack, "tx" |)
                     ],
                     make_dict []
                   |)
@@ -2409,10 +2423,10 @@ Definition recover_sender : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -2421,15 +2435,15 @@ Definition recover_sender : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "public_key" ,
                   M.call (|
-                    M.get_name (| globals, "secp256k1_recover" |),
+                    M.get_name (| globals, locals_stack, "secp256k1_recover" |),
                     make_list [
-                      M.get_name (| globals, "r" |);
-                      M.get_name (| globals, "s" |);
-                      M.get_field (| M.get_name (| globals, "tx" |), "y_parity" |);
+                      M.get_name (| globals, locals_stack, "r" |);
+                      M.get_name (| globals, locals_stack, "s" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "y_parity" |);
                       M.call (|
-                        M.get_name (| globals, "signing_hash_1559" |),
+                        M.get_name (| globals, locals_stack, "signing_hash_1559" |),
                         make_list [
-                          M.get_name (| globals, "tx" |)
+                          M.get_name (| globals, locals_stack, "tx" |)
                         ],
                         make_dict []
                       |)
@@ -2448,13 +2462,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2469,8 +2483,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2486,12 +2501,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2502,8 +2517,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2521,19 +2537,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2549,8 +2565,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_2930 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 2930 signature.
 
@@ -2566,14 +2583,14 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "01",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2585,8 +2602,9 @@ Definition signing_hash_2930 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_1559 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 1559 signature.
 
@@ -2602,14 +2620,14 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           BinOp.add (|
             Constant.bytes "02",
             M.call (|
-              M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
               make_list [
-                make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_field (| M.get_name (| globals, "tx" |), "access_list" |) ]
+                make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "chain_id" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_priority_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "max_fee_per_gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "access_list" |) ]
               ],
               make_dict []
             |)
@@ -2621,8 +2639,9 @@ Definition signing_hash_1559 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2656,12 +2675,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2672,8 +2691,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2704,18 +2724,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2732,10 +2752,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2752,8 +2772,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
diff --git a/CoqOfPython/ethereum/shanghai/fork_types.v b/CoqOfPython/ethereum/shanghai/fork_types.v
index ce691e3..e9b6291 100644
--- a/CoqOfPython/ethereum/shanghai/fork_types.v
+++ b/CoqOfPython/ethereum/shanghai/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.fork_types".
+Definition globals : Globals.t := "ethereum.shanghai.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/shanghai/state.v b/CoqOfPython/ethereum/shanghai/state.v
index 6c39384..18226ab 100644
--- a/CoqOfPython/ethereum/shanghai/state.v
+++ b/CoqOfPython/ethereum/shanghai/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.state".
+Definition globals : Globals.t := "ethereum.shanghai.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,21 +90,23 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -115,12 +119,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -130,8 +134,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -141,18 +146,18 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -164,8 +169,9 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -176,9 +182,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -186,11 +192,11 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "clear" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "clear" |),
     make_list [],
     make_dict []
   |) in
@@ -202,8 +208,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -226,10 +233,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -238,31 +245,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -282,22 +290,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -312,19 +321,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -340,18 +350,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -359,8 +369,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -375,14 +386,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -392,8 +403,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition mark_account_created : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark an account as having been created in the current transaction.
     This information is used by `get_storage_original()` to handle an obscure
@@ -411,17 +423,18 @@ Definition mark_account_created : Value.t -> Value.t -> M :=
         Address of the account that has been created.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -443,9 +456,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -454,14 +467,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -476,30 +489,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -517,10 +531,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -529,9 +543,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -540,7 +554,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -548,17 +562,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -566,11 +580,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -578,14 +592,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -595,8 +609,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -612,23 +627,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -638,15 +653,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -660,13 +676,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -674,8 +690,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -694,10 +711,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -707,8 +724,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -728,10 +746,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -739,9 +757,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -750,7 +768,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -759,8 +777,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -780,10 +799,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -791,9 +810,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -803,12 +822,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -819,8 +838,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -841,10 +861,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -852,15 +872,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -870,12 +890,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -888,8 +908,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -908,10 +929,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -920,7 +941,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -934,9 +955,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -946,12 +967,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -964,28 +985,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -995,54 +1017,57 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition process_withdrawal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "wd" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "wd" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increase the balance of the withdrawing account.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "wd" |), "address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "wd" |), "address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -1059,19 +1084,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1087,21 +1113,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1113,8 +1139,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1128,19 +1155,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1157,19 +1185,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition get_storage_original : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the original value in a storage slot i.e. the value before the current
     transaction began. This function reads the value from the snapshots taken
@@ -1188,14 +1217,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_created_accounts" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_created_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1208,18 +1237,18 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "_" |); M.get_name (| globals, "original_trie" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "_" |); M.get_name (| globals, locals_stack, "original_trie" |) ],
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |),
         Constant.int 0
       |)
     |) in
     let _ := M.assign_local (|
       "original_account_trie" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "original_trie" |), "get" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "original_trie" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1228,7 +1257,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "original_account_trie" |),
+          M.get_name (| globals, locals_stack, "original_account_trie" |),
           Constant.None_
         |),
       (* then *)
@@ -1236,7 +1265,7 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1249,10 +1278,10 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "original_value" ,
           M.call (|
-            M.get_name (| globals, "trie_get" |),
+            M.get_name (| globals, locals_stack, "trie_get" |),
             make_list [
-              M.get_name (| globals, "original_account_trie" |);
-              M.get_name (| globals, "key" |)
+              M.get_name (| globals, locals_stack, "original_account_trie" |);
+              M.get_name (| globals, locals_stack, "key" |)
             ],
             make_dict []
           |)
@@ -1260,14 +1289,14 @@ Definition get_storage_original : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "original_value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "original_value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "original_value" |)
+      M.get_name (| globals, locals_stack, "original_value" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/transactions.v b/CoqOfPython/ethereum/shanghai/transactions.v
index 76f69cd..e7408ca 100644
--- a/CoqOfPython/ethereum/shanghai/transactions.v
+++ b/CoqOfPython/ethereum/shanghai/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.transactions".
+Definition globals : Globals.t := "ethereum.shanghai.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,14 +99,15 @@ Definition FeeMarketTransaction : Value.t :=
 
 Definition Transaction : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "AccessListTransaction" |); M.get_name (| globals, "FeeMarketTransaction" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "AccessListTransaction" |); M.get_name (| globals, locals_stack, "FeeMarketTransaction" |) ]
   |)
 )).
 
 Definition encode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -112,17 +115,17 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "LegacyTransaction" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "LegacyTransaction" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -131,10 +134,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "AccessListTransaction" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "AccessListTransaction" |)
               ],
               make_dict []
             |),
@@ -144,9 +147,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               BinOp.add (|
                 Constant.bytes "01",
                 M.call (|
-                  M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                   make_list [
-                    M.get_name (| globals, "tx" |)
+                    M.get_name (| globals, locals_stack, "tx" |)
                   ],
                   make_dict []
                 |)
@@ -159,10 +162,10 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "tx" |);
-                    M.get_name (| globals, "FeeMarketTransaction" |)
+                    M.get_name (| globals, locals_stack, "tx" |);
+                    M.get_name (| globals, locals_stack, "FeeMarketTransaction" |)
                   ],
                   make_dict []
                 |),
@@ -172,9 +175,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
                   BinOp.add (|
                     Constant.bytes "02",
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                       make_list [
-                        M.get_name (| globals, "tx" |)
+                        M.get_name (| globals, locals_stack, "tx" |)
                       ],
                       make_dict []
                     |)
@@ -184,7 +187,7 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.raise (| Some (M.call (|
-                  M.get_name (| globals, "Exception" |),
+                  M.get_name (| globals, locals_stack, "Exception" |),
                   make_list [
                     Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                   ],
@@ -199,8 +202,9 @@ Definition encode_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition decode_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decode a transaction. Needed because non-legacy transactions aren't RLP.
     " in
@@ -208,10 +212,10 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "tx" |);
-            M.get_name (| globals, "Bytes" |)
+            M.get_name (| globals, locals_stack, "tx" |);
+            M.get_name (| globals, locals_stack, "Bytes" |)
           ],
           make_dict []
         |),
@@ -222,7 +226,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           M.if_then_else (|
             Compare.eq (|
               M.get_subscript (|
-                M.get_name (| globals, "tx" |),
+                M.get_name (| globals, locals_stack, "tx" |),
                 Constant.int 0
               |),
               Constant.int 1
@@ -231,11 +235,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                 make_list [
-                  M.get_name (| globals, "AccessListTransaction" |);
+                  M.get_name (| globals, locals_stack, "AccessListTransaction" |);
                   M.slice (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 1,
                     Constant.None_,
                     Constant.None_
@@ -252,7 +256,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               M.if_then_else (|
                 Compare.eq (|
                   M.get_subscript (|
-                    M.get_name (| globals, "tx" |),
+                    M.get_name (| globals, locals_stack, "tx" |),
                     Constant.int 0
                   |),
                   Constant.int 2
@@ -261,11 +265,11 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "rlp" |), "decode_to" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "decode_to" |),
                     make_list [
-                      M.get_name (| globals, "FeeMarketTransaction" |);
+                      M.get_name (| globals, locals_stack, "FeeMarketTransaction" |);
                       M.slice (|
-                        M.get_name (| globals, "tx" |),
+                        M.get_name (| globals, locals_stack, "tx" |),
                         Constant.int 1,
                         Constant.None_,
                         Constant.None_
@@ -277,7 +281,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
-                let _ := M.raise (| Some (M.get_name (| globals, "InvalidBlock" |)) |) in
+                let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidBlock" |)) |) in
                 M.pure Constant.None_
               )) |) in
             M.pure Constant.None_
@@ -286,7 +290,7 @@ Definition decode_transaction : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         |) in
         M.pure Constant.None_
       )) |) in
diff --git a/CoqOfPython/ethereum/shanghai/trie.v b/CoqOfPython/ethereum/shanghai/trie.v
index 3192625..2a44bc7 100644
--- a/CoqOfPython/ethereum/shanghai/trie.v
+++ b/CoqOfPython/ethereum/shanghai/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.trie".
+Definition globals : Globals.t := "ethereum.shanghai.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -91,10 +93,10 @@ Axiom ethereum_shanghai_transactions_imports_LegacyTransaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -107,14 +109,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); M.get_name (| globals, "Withdrawal" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); M.get_name (| globals, locals_stack, "Withdrawal" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -124,41 +126,41 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
+        M.get_name (| globals, locals_stack, "Optional" |),
         M.get_subscript (|
-          M.get_name (| globals, "Union" |),
-          make_tuple [ M.get_name (| globals, "Withdrawal" |); M.get_name (| globals, "Bytes" |) ]
+          M.get_name (| globals, locals_stack, "Union" |),
+          make_tuple [ M.get_name (| globals, locals_stack, "Withdrawal" |); M.get_name (| globals, locals_stack, "Bytes" |) ]
         |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -196,14 +198,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -227,7 +230,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -243,10 +246,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -255,13 +258,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -270,10 +273,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -282,13 +285,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -297,10 +300,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -309,9 +312,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -319,7 +322,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -336,9 +339,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -348,9 +351,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -359,16 +362,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -378,8 +381,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -389,25 +393,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -419,10 +423,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "LegacyTransaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Withdrawal" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "LegacyTransaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Withdrawal" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -430,13 +434,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -451,27 +455,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -495,8 +499,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -513,14 +518,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -531,8 +536,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -552,8 +558,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -561,14 +567,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -580,18 +586,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -611,10 +618,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -622,21 +629,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -649,11 +657,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -661,12 +669,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -674,7 +682,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -689,9 +697,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -699,8 +707,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -737,7 +746,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -748,9 +757,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -761,13 +770,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -775,15 +784,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -793,20 +802,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -824,7 +833,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -832,13 +841,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -847,15 +856,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -865,20 +874,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -896,9 +905,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -906,8 +915,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -924,14 +934,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -942,26 +952,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -969,17 +979,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -991,9 +1001,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -1001,8 +1011,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1023,9 +1034,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1034,25 +1045,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1060,13 +1071,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1080,9 +1091,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1090,13 +1101,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1104,15 +1115,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1122,22 +1133,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1146,13 +1157,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1173,10 +1185,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1184,14 +1196,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1209,12 +1221,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1227,12 +1239,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1244,18 +1256,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1265,8 +1277,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1290,9 +1303,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1311,12 +1324,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1329,9 +1342,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1342,24 +1355,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1369,8 +1382,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1378,31 +1391,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1417,7 +1430,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1438,7 +1451,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1446,30 +1459,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1489,9 +1502,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1499,7 +1512,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1517,21 +1530,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1539,19 +1552,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1560,8 +1573,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1570,17 +1583,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1593,10 +1606,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/utils/__init__.v b/CoqOfPython/ethereum/shanghai/utils/__init__.v
index 5a9b965..043dac7 100644
--- a/CoqOfPython/ethereum/shanghai/utils/__init__.v
+++ b/CoqOfPython/ethereum/shanghai/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.utils.__init__".
+Definition globals : Globals.t := "ethereum.shanghai.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/shanghai/utils/address.v b/CoqOfPython/ethereum/shanghai/utils/address.v
index 309f4c7..d0b9263 100644
--- a/CoqOfPython/ethereum/shanghai/utils/address.v
+++ b/CoqOfPython/ethereum/shanghai/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.utils.address".
+Definition globals : Globals.t := "ethereum.shanghai.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -41,8 +43,9 @@ Axiom ethereum_shanghai_fork_types_imports_Address :
   IsImported globals "ethereum.shanghai.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -58,11 +61,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -77,8 +80,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -98,14 +102,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -117,7 +121,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -126,9 +130,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -136,9 +140,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
@@ -146,8 +150,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "salt"; "call_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "salt"; "call_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created, which is
     based on the sender address, salt and the call data as well.
@@ -172,14 +177,14 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
         BinOp.add (|
           BinOp.add (|
             Constant.bytes "ff",
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "salt" |)
+          M.get_name (| globals, locals_stack, "salt" |)
         |),
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |)
@@ -188,9 +193,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "preimage" |)
+          M.get_name (| globals, locals_stack, "preimage" |)
         ],
         make_dict []
       |)
@@ -198,7 +203,7 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -207,9 +212,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -217,9 +222,9 @@ Definition compute_create2_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/utils/hexadecimal.v b/CoqOfPython/ethereum/shanghai/utils/hexadecimal.v
index d044fd0..460325a 100644
--- a/CoqOfPython/ethereum/shanghai/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/shanghai/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.shanghai.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_shanghai_fork_types_imports_Root :
   IsImported globals "ethereum.shanghai.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/shanghai/utils/message.v b/CoqOfPython/ethereum/shanghai/utils/message.v
index d1e2dbc..918b127 100644
--- a/CoqOfPython/ethereum/shanghai/utils/message.v
+++ b/CoqOfPython/ethereum/shanghai/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.utils.message".
+Definition globals : Globals.t := "ethereum.shanghai.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -56,8 +58,9 @@ Axiom ethereum_shanghai_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.shanghai.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value"; "is_static"; "preaccessed_addresses"; "preaccessed_storage_keys" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -99,10 +102,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -111,20 +114,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -138,7 +141,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -147,7 +150,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -156,10 +159,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -167,19 +170,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -188,14 +191,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -206,7 +209,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -219,30 +222,30 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "accessed_addresses" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "current_target" |)
+      M.get_name (| globals, locals_stack, "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "caller" |)
+      M.get_name (| globals, locals_stack, "caller" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "PRE_COMPILED_CONTRACTS" |), "keys" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "PRE_COMPILED_CONTRACTS" |), "keys" |),
         make_list [],
         make_dict []
       |)
@@ -250,15 +253,15 @@ Definition prepare_message : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "accessed_addresses" |), "update" |),
     make_list [
-      M.get_name (| globals, "preaccessed_addresses" |)
+      M.get_name (| globals, locals_stack, "preaccessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/__init__.v b/CoqOfPython/ethereum/shanghai/vm/__init__.v
index 1cfebb9..2c94399 100644
--- a/CoqOfPython/ethereum/shanghai/vm/__init__.v
+++ b/CoqOfPython/ethereum/shanghai/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.__init__".
+Definition globals : Globals.t := "ethereum.shanghai.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -97,8 +99,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -111,30 +114,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -142,19 +145,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -164,24 +167,25 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_addresses" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_addresses" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accessed_storage_keys" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accessed_storage_keys" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -196,15 +200,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -217,8 +221,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -226,19 +230,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -254,7 +258,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/exceptions.v b/CoqOfPython/ethereum/shanghai/vm/exceptions.v
index b659bce..b62f125 100644
--- a/CoqOfPython/ethereum/shanghai/vm/exceptions.v
+++ b/CoqOfPython/ethereum/shanghai/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.exceptions".
+Definition globals : Globals.t := "ethereum.shanghai.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -79,22 +81,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/shanghai/vm/gas.v b/CoqOfPython/ethereum/shanghai/vm/gas.v
index 3604b0f..4271a86 100644
--- a/CoqOfPython/ethereum/shanghai/vm/gas.v
+++ b/CoqOfPython/ethereum/shanghai/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.gas".
+Definition globals : Globals.t := "ethereum.shanghai.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_shanghai_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -86,7 +88,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 4800
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -116,7 +118,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -126,7 +128,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -136,7 +138,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -166,7 +168,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -176,7 +178,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -196,7 +198,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -206,7 +208,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -216,7 +218,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -226,7 +228,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -236,7 +238,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -246,7 +248,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -256,7 +258,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -266,7 +268,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -276,7 +278,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -286,7 +288,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -296,7 +298,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -306,7 +308,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -326,7 +328,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -336,7 +338,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -346,7 +348,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -356,7 +358,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -366,7 +368,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -376,7 +378,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -386,7 +388,7 @@ Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -396,7 +398,7 @@ Definition GAS_RETURN_DATA_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -406,7 +408,7 @@ Definition GAS_FAST_STEP : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -416,7 +418,7 @@ Definition GAS_BLAKE2_PER_ROUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2100
     ],
@@ -426,7 +428,7 @@ Definition GAS_COLD_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2600
     ],
@@ -436,7 +438,7 @@ Definition GAS_COLD_ACCOUNT_ACCESS : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_WARM_ACCESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 100
     ],
@@ -469,8 +471,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -483,13 +486,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -500,22 +503,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -525,8 +528,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -546,9 +550,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -558,15 +562,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -575,16 +579,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -603,7 +608,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -613,7 +618,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -623,12 +628,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -638,14 +643,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -659,9 +664,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -669,20 +674,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -695,8 +700,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -710,16 +715,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -727,9 +732,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -738,13 +743,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -754,10 +759,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -765,8 +770,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -797,13 +803,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -811,32 +817,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -850,18 +856,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -872,15 +878,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -889,8 +895,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -906,9 +913,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
@@ -916,8 +923,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition init_code_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "init_code_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "init_code_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas to be charged for the init code in CREAT*
     opcodes as well as create transactions.
@@ -936,11 +944,11 @@ Definition init_code_cost : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BinOp.floor_div (|
         BinOp.mult (|
-          M.get_name (| globals, "GAS_INIT_CODE_WORD_COST" |),
+          M.get_name (| globals, locals_stack, "GAS_INIT_CODE_WORD_COST" |),
           M.call (|
-            M.get_name (| globals, "ceil32" |),
+            M.get_name (| globals, locals_stack, "ceil32" |),
             make_list [
-              M.get_name (| globals, "init_code_length" |)
+              M.get_name (| globals, locals_stack, "init_code_length" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/__init__.v b/CoqOfPython/ethereum/shanghai/vm/instructions/__init__.v
index bf085c7..3e8b12d 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/shanghai/vm/instructions/arithmetic.v
index d62c2ed..87c5f1b 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/bitwise.v b/CoqOfPython/ethereum/shanghai/vm/instructions/bitwise.v
index 5e49a28..30a1e49 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -51,9 +54,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -61,42 +64,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -110,9 +114,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -120,42 +124,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -169,9 +174,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,42 +184,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -228,39 +234,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -275,9 +282,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -285,18 +292,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -304,7 +311,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -312,7 +319,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -326,15 +333,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -342,16 +349,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -359,23 +366,24 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shl : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift left (SHL) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -387,9 +395,9 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -397,18 +405,18 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -416,7 +424,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -424,14 +432,14 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.l_shift (|
-                  M.get_name (| globals, "value" |),
-                  M.get_name (| globals, "shift" |)
+                  M.get_name (| globals, locals_stack, "value" |),
+                  M.get_name (| globals, locals_stack, "shift" |)
                 |),
-                M.get_name (| globals, "U256_CEIL_VALUE" |)
+                M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
               |)
             ],
             make_dict []
@@ -443,7 +451,7 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -453,23 +461,24 @@ Definition bitwise_shl : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_shr : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Logical shift right (SHR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -481,9 +490,9 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -491,18 +500,18 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -510,7 +519,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -518,8 +527,8 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "value" |),
-            M.get_name (| globals, "shift" |)
+            M.get_name (| globals, locals_stack, "value" |),
+            M.get_name (| globals, locals_stack, "shift" |)
           |)
         |) in
         M.pure Constant.None_
@@ -528,7 +537,7 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -538,23 +547,24 @@ Definition bitwise_shr : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_sar : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Arithmetic shift right (SAR) operation of the top 2 elements of the stack.
     Pushes the result back on the stack.
@@ -566,9 +576,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "shift" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -577,9 +587,9 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       "signed_value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -588,10 +598,10 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -599,7 +609,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "shift" |),
+          M.get_name (| globals, locals_stack, "shift" |),
           Constant.int 256
         |),
       (* then *)
@@ -607,11 +617,11 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
             make_list [
               BinOp.r_shift (|
-                M.get_name (| globals, "signed_value" |),
-                M.get_name (| globals, "shift" |)
+                M.get_name (| globals, locals_stack, "signed_value" |),
+                M.get_name (| globals, locals_stack, "shift" |)
               |)
             ],
             make_dict []
@@ -624,7 +634,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.gt_e (|
-              M.get_name (| globals, "signed_value" |),
+              M.get_name (| globals, locals_stack, "signed_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -632,7 +642,7 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -644,23 +654,23 @@ Definition bitwise_sar : Value.t -> Value.t -> M :=
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "result" ,
-              M.get_field (| M.get_name (| globals, "U256" |), "MAX_VALUE" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "MAX_VALUE" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/block.v b/CoqOfPython/ethereum/shanghai/vm/instructions/block.v
index 72e72da..cd0188d 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -57,18 +60,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -77,14 +80,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -102,23 +105,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -127,14 +130,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -156,21 +160,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -179,14 +183,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -208,31 +213,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -253,21 +259,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -276,14 +282,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition prev_randao : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the `prev_randao` value onto the stack.
 
@@ -304,21 +311,21 @@ Definition prev_randao : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "prev_randao" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "prev_randao" |)
         ],
         make_dict []
       |)
@@ -327,14 +334,15 @@ Definition prev_randao : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -355,21 +363,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -378,14 +386,15 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition chain_id : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the chain id onto the stack.
 
@@ -403,21 +412,21 @@ Definition chain_id : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "chain_id" |)
         ],
         make_dict []
       |)
@@ -426,7 +435,7 @@ Definition chain_id : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/comparison.v b/CoqOfPython/ethereum/shanghai/vm/instructions/comparison.v
index 53c9557..121bfa8 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/control_flow.v b/CoqOfPython/ethereum/shanghai/vm/instructions/control_flow.v
index e43ea45..1cf5348 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/environment.v b/CoqOfPython/ethereum/shanghai/vm/instructions/environment.v
index 17798fb..a745422 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -76,8 +78,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -89,21 +92,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -112,14 +115,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -132,12 +136,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -149,16 +153,16 @@ Definition balance : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -166,17 +170,17 @@ Definition balance : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -185,32 +189,33 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -223,21 +228,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -246,14 +251,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -265,21 +271,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -288,14 +294,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -307,31 +314,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -345,30 +353,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -379,13 +387,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -394,14 +402,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -413,24 +422,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -442,14 +451,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -465,9 +475,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -475,9 +485,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -485,9 +495,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -496,12 +506,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -514,76 +524,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -595,24 +606,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -624,14 +635,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -647,9 +659,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -657,9 +669,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -667,9 +679,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -678,12 +690,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -696,76 +708,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -777,21 +790,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -800,14 +813,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -820,12 +834,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -837,16 +851,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -854,17 +868,17 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -873,16 +887,16 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -894,23 +908,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -923,12 +938,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -939,9 +954,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -949,9 +964,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -959,9 +974,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -970,12 +985,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -988,18 +1003,18 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
@@ -1009,21 +1024,21 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_WARM_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1032,22 +1047,22 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -1056,19 +1071,19 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -1076,34 +1091,35 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the size of the return data buffer onto the stack.
 
@@ -1114,24 +1130,24 @@ Definition returndatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
             ],
             make_dict []
           |)
@@ -1143,14 +1159,15 @@ Definition returndatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition returndatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copies data from the return data buffer code to memory
 
@@ -1162,9 +1179,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1172,9 +1189,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "return_data_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1182,9 +1199,9 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1193,12 +1210,12 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -1211,108 +1228,109 @@ Definition returndatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_RETURN_DATA_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_RETURN_DATA_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "return_data_start_position" |)
+              M.get_name (| globals, locals_stack, "return_data_start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "return_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfBoundsRead" |)
+      M.get_name (| globals, locals_stack, "OutOfBoundsRead" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-        M.get_name (| globals, "return_data_start_position" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+        M.get_name (| globals, locals_stack, "return_data_start_position" |),
         BinOp.add (|
-          M.get_name (| globals, "return_data_start_position" |),
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "return_data_start_position" |),
+          M.get_name (| globals, locals_stack, "size" |)
         |),
         Constant.None_
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodehash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Returns the keccak256 hash of a contract’s bytecode
     Parameters
@@ -1323,12 +1341,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1340,16 +1358,16 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1357,17 +1375,17 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -1376,10 +1394,10 @@ Definition extcodehash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -1388,15 +1406,15 @@ Definition extcodehash : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "account" |),
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "account" |),
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -1409,12 +1427,12 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "codehash" ,
           M.call (|
-            M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "keccak256" |),
+                M.get_name (| globals, locals_stack, "keccak256" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |)
                 ],
                 make_dict []
               |)
@@ -1425,23 +1443,24 @@ Definition extcodehash : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codehash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codehash" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition self_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the current address to the stack.
 
@@ -1453,42 +1472,43 @@ Definition self_balance : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_FAST_STEP" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_FAST_STEP" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition base_fee : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the base fee of the current block on to the stack.
 
@@ -1500,21 +1520,21 @@ Definition base_fee : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "base_fee_per_gas" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "base_fee_per_gas" |)
         ],
         make_dict []
       |)
@@ -1523,7 +1543,7 @@ Definition base_fee : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/keccak.v b/CoqOfPython/ethereum/shanghai/vm/instructions/keccak.v
index 1565118..70897e7 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/log.v b/CoqOfPython/ethereum/shanghai/vm/instructions/log.v
index b7f272a..4d0abf6 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -53,8 +55,9 @@ Axiom ethereum_shanghai_vm_stack_imports_pop :
   IsImported globals "ethereum.shanghai.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -72,9 +75,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -82,9 +85,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -95,11 +98,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -108,9 +111,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -119,9 +122,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -134,82 +137,82 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -217,9 +220,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -227,9 +230,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -237,9 +240,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -247,9 +250,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/memory.v b/CoqOfPython/ethereum/shanghai/vm/instructions/memory.v
index f71e369..f195df9 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/stack.v b/CoqOfPython/ethereum/shanghai/vm/instructions/stack.v
index 8c4b767..e18a708 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_shanghai_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.shanghai.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack. Push zero if num_bytes is zero.
 
@@ -100,16 +104,16 @@ Definition push_n : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "num_bytes" |),
+          M.get_name (| globals, locals_stack, "num_bytes" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
@@ -117,10 +121,10 @@ Definition push_n : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -129,26 +133,26 @@ Definition push_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -160,26 +164,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -195,67 +200,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -275,64 +281,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -340,9 +346,9 @@ Definition push0 : Value.t := M.run ltac:(M.monadic (
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -350,9 +356,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -360,9 +366,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -370,9 +376,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -380,9 +386,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -390,9 +396,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -400,9 +406,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -410,9 +416,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -420,9 +426,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -430,9 +436,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -440,9 +446,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -450,9 +456,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -460,9 +466,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -470,9 +476,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -480,9 +486,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -490,9 +496,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -500,9 +506,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -510,9 +516,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -520,9 +526,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -530,9 +536,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -540,9 +546,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -550,9 +556,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -560,9 +566,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -570,9 +576,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -580,9 +586,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -590,9 +596,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -600,9 +606,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -610,9 +616,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -620,9 +626,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -630,9 +636,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -640,9 +646,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -650,9 +656,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -660,9 +666,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -670,9 +676,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -680,9 +686,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -690,9 +696,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -700,9 +706,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -710,9 +716,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -720,9 +726,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -730,9 +736,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -740,9 +746,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -750,9 +756,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -760,9 +766,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -770,9 +776,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -780,9 +786,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -790,9 +796,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -800,9 +806,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -810,9 +816,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -820,9 +826,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -830,9 +836,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -840,9 +846,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -850,9 +856,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -860,9 +866,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -870,9 +876,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -880,9 +886,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -890,9 +896,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -900,9 +906,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -910,9 +916,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -920,9 +926,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -930,9 +936,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -940,9 +946,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -950,9 +956,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -960,9 +966,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -970,9 +976,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/storage.v b/CoqOfPython/ethereum/shanghai/vm/instructions/storage.v
index a05890f..0e9b0a7 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -59,8 +61,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -75,9 +78,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -89,16 +92,16 @@ Definition sload : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_WARM_ACCESS" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
     ],
     make_dict []
   |) in
@@ -106,17 +109,17 @@ Definition sload : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_COLD_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
     ],
     make_dict []
   |) in
@@ -125,33 +128,34 @@ Definition sload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -165,9 +169,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -178,32 +182,32 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-        M.get_name (| globals, "GAS_CALL_STIPEND" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+        M.get_name (| globals, locals_stack, "GAS_CALL_STIPEND" |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "original_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage_original" |),
+        M.get_name (| globals, locals_stack, "get_storage_original" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -211,11 +215,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -223,7 +227,7 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_cost" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -234,22 +238,22 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ],
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |)
+          make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ],
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_storage_keys" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_storage_keys" |), "add" |),
     make_list [
-      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |); M.get_name (| globals, "key" |) ]
+      make_tuple [ M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |); M.get_name (| globals, locals_stack, "key" |) ]
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -261,13 +265,13 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "original_value" |),
-            M.get_name (| globals, "current_value" |)
+            M.get_name (| globals, locals_stack, "original_value" |),
+            M.get_name (| globals, locals_stack, "current_value" |)
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "current_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |)
           ))
         |),
@@ -277,7 +281,7 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
+              M.get_name (| globals, locals_stack, "original_value" |),
               Constant.int 0
             |),
           (* then *)
@@ -285,7 +289,7 @@ Definition sstore : Value.t -> Value.t -> M :=
             let _ := M.assign_op_local (|
               BinOp.add,
               "gas_cost",
-              M.get_name (| globals, "GAS_STORAGE_SET" |)
+              M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -294,8 +298,8 @@ Definition sstore : Value.t -> Value.t -> M :=
               BinOp.add,
               "gas_cost",
               BinOp.sub (|
-    M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-    M.get_name (| globals, "GAS_COLD_SLOAD" |)
+    M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+    M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
   |)
             |) in
             M.pure Constant.None_
@@ -306,7 +310,7 @@ Definition sstore : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -314,8 +318,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "current_value" |),
-          M.get_name (| globals, "new_value" |)
+          M.get_name (| globals, locals_stack, "current_value" |),
+          M.get_name (| globals, locals_stack, "new_value" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -324,18 +328,18 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 BoolOp.and (|
                   Compare.not_eq (|
-                    M.get_name (| globals, "current_value" |),
+                    M.get_name (| globals, locals_stack, "current_value" |),
                     Constant.int 0
                   |),
                   ltac:(M.monadic (
                     Compare.eq (|
-                      M.get_name (| globals, "new_value" |),
+                      M.get_name (| globals, locals_stack, "new_value" |),
                       Constant.int 0
                     |)
                   ))
@@ -346,11 +350,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.add,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -365,12 +369,12 @@ Definition sstore : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.not_eq (|
-                M.get_name (| globals, "original_value" |),
+                M.get_name (| globals, locals_stack, "original_value" |),
                 Constant.int 0
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "current_value" |),
+                  M.get_name (| globals, locals_stack, "current_value" |),
                   Constant.int 0
                 |)
               ))
@@ -379,11 +383,11 @@ Definition sstore : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_op (|
               BinOp.sub,
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
               M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
-      M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+      M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
     ],
     make_dict []
   |)
@@ -397,8 +401,8 @@ Definition sstore : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "original_value" |),
-              M.get_name (| globals, "new_value" |)
+              M.get_name (| globals, locals_stack, "original_value" |),
+              M.get_name (| globals, locals_stack, "new_value" |)
             |),
           (* then *)
           ltac:(M.monadic (
@@ -406,20 +410,20 @@ Definition sstore : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.eq (|
-                  M.get_name (| globals, "original_value" |),
+                  M.get_name (| globals, locals_stack, "original_value" |),
                   Constant.int 0
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
-        M.get_name (| globals, "GAS_STORAGE_SET" |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |),
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -430,16 +434,16 @@ Definition sstore : Value.t -> Value.t -> M :=
               )), ltac:(M.monadic (
                 let _ := M.assign_op (|
                   BinOp.add,
-                  M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
                   M.call (|
-    M.get_name (| globals, "int" |),
+    M.get_name (| globals, locals_stack, "int" |),
     make_list [
       BinOp.sub (|
         BinOp.sub (|
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |),
-          M.get_name (| globals, "GAS_COLD_SLOAD" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |),
+          M.get_name (| globals, locals_stack, "GAS_COLD_SLOAD" |)
         |),
-        M.get_name (| globals, "GAS_WARM_ACCESS" |)
+        M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
       |)
     ],
     make_dict []
@@ -458,34 +462,34 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/instructions/system.v b/CoqOfPython/ethereum/shanghai/vm/instructions/system.v
index 4fc7b71..82dbbcc 100644
--- a/CoqOfPython/ethereum/shanghai/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/shanghai/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.shanghai.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,8 +111,9 @@ Axiom ethereum_shanghai_vm_stack_imports_push :
   IsImported globals "ethereum.shanghai.vm.stack" "push".
 
 Definition generic_create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size"; "init_code_gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "endowment"; "contract_address"; "memory_start_position"; "memory_size"; "init_code_gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Core logic used by the `CREATE*` family of opcodes.
     " in
@@ -118,51 +121,51 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "call_data" |)
+            M.get_name (| globals, locals_stack, "call_data" |)
           ],
           make_dict []
         |),
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "MAX_CODE_SIZE" |)
+          M.get_name (| globals, locals_stack, "MAX_CODE_SIZE" |)
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "contract_address" |)
+      M.get_name (| globals, locals_stack, "contract_address" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -172,32 +175,32 @@ Definition generic_create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -207,15 +210,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -231,10 +234,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -244,15 +247,15 @@ Definition generic_create : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -273,29 +276,29 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_has_code_or_nonce" |),
+          M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "contract_address" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "contract_address" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -313,17 +316,17 @@ Definition generic_create : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -331,10 +334,10 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_create_message" |),
+        M.get_name (| globals, locals_stack, "process_create_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -342,27 +345,27 @@ Definition generic_create : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -375,25 +378,25 @@ Definition generic_create : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -405,8 +408,9 @@ Definition generic_create : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -418,9 +422,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -428,9 +432,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -438,9 +442,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -448,11 +452,11 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -461,12 +465,12 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "init_code_gas" ,
       M.call (|
-        M.get_name (| globals, "init_code_cost" |),
+        M.get_name (| globals, locals_stack, "init_code_cost" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "memory_size" |)
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -475,38 +479,38 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_CREATE" |),
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+          M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
         |),
-        M.get_name (| globals, "init_code_gas" |)
+        M.get_name (| globals, locals_stack, "init_code_gas" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -515,27 +519,28 @@ Definition create : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |);
-      M.get_name (| globals, "init_code_gas" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |);
+      M.get_name (| globals, locals_stack, "init_code_gas" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition create2 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -550,9 +555,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -560,9 +565,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -570,9 +575,9 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -581,9 +586,9 @@ Definition create2 : Value.t -> Value.t -> M :=
       "salt" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -594,11 +599,11 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
@@ -608,12 +613,12 @@ Definition create2 : Value.t -> Value.t -> M :=
       "call_data_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "memory_size" |)
+                M.get_name (| globals, locals_stack, "memory_size" |)
               ],
               make_dict []
             |)
@@ -626,12 +631,12 @@ Definition create2 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "init_code_gas" ,
       M.call (|
-        M.get_name (| globals, "init_code_cost" |),
+        M.get_name (| globals, locals_stack, "init_code_cost" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "memory_size" |)
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -640,46 +645,46 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_CREATE" |),
+            M.get_name (| globals, locals_stack, "GAS_CREATE" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-              M.get_name (| globals, "call_data_words" |)
+              M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+              M.get_name (| globals, locals_stack, "call_data_words" |)
             |)
           |),
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
         |),
-        M.get_name (| globals, "init_code_gas" |)
+        M.get_name (| globals, locals_stack, "init_code_gas" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_create2_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_create2_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "salt" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "salt" |);
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "memory_start_position" |);
-              M.get_name (| globals, "memory_size" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "memory_start_position" |);
+              M.get_name (| globals, locals_stack, "memory_size" |)
             ],
             make_dict []
           |)
@@ -688,27 +693,28 @@ Definition create2 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_create" |),
+    M.get_name (| globals, locals_stack, "generic_create" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "endowment" |);
-      M.get_name (| globals, "contract_address" |);
-      M.get_name (| globals, "memory_start_position" |);
-      M.get_name (| globals, "memory_size" |);
-      M.get_name (| globals, "init_code_gas" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "endowment" |);
+      M.get_name (| globals, locals_stack, "contract_address" |);
+      M.get_name (| globals, locals_stack, "memory_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_size" |);
+      M.get_name (| globals, locals_stack, "init_code_gas" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -720,9 +726,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -730,9 +736,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -740,63 +746,64 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "is_staticcall"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
 (* At stmt: unsupported node type: ImportFrom *)
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
       Constant.bytes ""
     |) in
     let _ :=
@@ -804,24 +811,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -841,11 +848,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -853,10 +860,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -864,7 +871,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -872,10 +879,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -883,27 +890,27 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -916,23 +923,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -946,16 +953,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -967,14 +974,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -983,8 +990,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -996,12 +1004,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1012,12 +1020,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1028,9 +1036,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1038,9 +1046,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1048,9 +1056,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1058,9 +1066,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1068,9 +1076,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1078,12 +1086,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1093,28 +1101,28 @@ Definition call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1124,16 +1132,16 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "to" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "to" |)
             ],
             make_dict []
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |)
           ))
@@ -1141,7 +1149,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1149,7 +1157,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -1157,13 +1165,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1171,56 +1179,56 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "access_gas_cost" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "access_gas_cost" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
-        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |),
+        UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
@@ -1229,25 +1237,25 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
           |)
         ))
       |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1256,17 +1264,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1276,32 +1284,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1309,14 +1317,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -1328,12 +1337,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1344,12 +1353,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1360,9 +1369,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1370,9 +1379,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1380,9 +1389,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1390,9 +1399,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1400,26 +1409,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1429,28 +1438,28 @@ Definition callcode : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -1459,13 +1468,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1473,58 +1482,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "access_gas_cost" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "access_gas_cost" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1533,17 +1542,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1553,32 +1562,32 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
     make_dict []
   |) in
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "return_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "return_data" |),
           Constant.bytes ""
         |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1586,14 +1595,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1605,12 +1615,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1620,28 +1630,28 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "beneficiary" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "beneficiary" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1653,20 +1663,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1679,7 +1689,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1687,32 +1697,32 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
-      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "is_static" |) |);
-      M.get_name (| globals, "WriteInStaticContext" |)
+      UnOp.not (| M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "is_static" |) |);
+      M.get_name (| globals, locals_stack, "WriteInStaticContext" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1720,33 +1730,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1756,9 +1766,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1766,19 +1776,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1788,15 +1798,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1808,12 +1819,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1824,12 +1835,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1840,9 +1851,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1850,9 +1861,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1860,9 +1871,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1870,9 +1881,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1880,12 +1891,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1895,104 +1906,105 @@ Definition delegatecall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "code_address" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "code_address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "code_address" |)
+      M.get_name (| globals, locals_stack, "code_address" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition staticcall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -2004,12 +2016,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2020,12 +2032,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -2036,9 +2048,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2046,9 +2058,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2056,9 +2068,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2066,9 +2078,9 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2076,12 +2088,12 @@ Definition staticcall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -2091,110 +2103,111 @@ Definition staticcall : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "to" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |)
+          M.get_name (| globals, locals_stack, "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_WARM_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_WARM_ACCESS" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accessed_addresses" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accessed_addresses" |), "add" |),
     make_list [
-      M.get_name (| globals, "to" |)
+      M.get_name (| globals, locals_stack, "to" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "access_gas_cost" ,
-          M.get_name (| globals, "GAS_COLD_ACCOUNT_ACCESS" |)
+          M.get_name (| globals, locals_stack, "GAS_COLD_ACCOUNT_ACCESS" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "access_gas_cost" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "access_gas_cost" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
         make_dict []
       |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition revert : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop execution and revert state changes, without consuming all provided gas
     and also has the ability to return a reason
@@ -2206,9 +2219,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2216,9 +2229,9 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -2226,54 +2239,54 @@ Definition revert : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "bytes" |),
+        M.get_name (| globals, locals_stack, "bytes" |),
         make_list [
-          M.get_name (| globals, "output" |)
+          M.get_name (| globals, locals_stack, "output" |)
         ],
         make_dict []
       |)
     |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "Revert" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "Revert" |)) |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/interpreter.v b/CoqOfPython/ethereum/shanghai/vm/interpreter.v
index f12f04a..6a8a73e 100644
--- a/CoqOfPython/ethereum/shanghai/vm/interpreter.v
+++ b/CoqOfPython/ethereum/shanghai/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.interpreter".
+Definition globals : Globals.t := "ethereum.shanghai.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -128,7 +130,7 @@ Axiom ethereum_shanghai_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -151,8 +153,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -174,9 +177,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -188,10 +191,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -199,44 +202,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -250,10 +253,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -266,10 +269,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -278,13 +281,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -294,12 +297,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -316,14 +319,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -331,7 +334,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -339,7 +342,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -351,22 +354,22 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
             ],
             make_dict []
           |)
@@ -376,29 +379,29 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -406,8 +409,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -424,43 +428,43 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "mark_account_created" |),
+    M.get_name (| globals, locals_stack, "mark_account_created" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -468,24 +472,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -493,22 +497,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -528,13 +533,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -546,17 +551,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -564,10 +569,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -575,12 +580,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -592,10 +597,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -603,13 +608,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -617,22 +622,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -650,14 +656,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -665,13 +671,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/memory.v b/CoqOfPython/ethereum/shanghai/vm/memory.v
index 6e9a8b2..a2fd291 100644
--- a/CoqOfPython/ethereum/shanghai/vm/memory.v
+++ b/CoqOfPython/ethereum/shanghai/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.memory".
+Definition globals : Globals.t := "ethereum.shanghai.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/__init__.v
index 4a90702..db1d979 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
@@ -67,7 +69,7 @@ Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x05"
     ],
@@ -77,7 +79,7 @@ Definition MODEXP_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x06"
     ],
@@ -87,7 +89,7 @@ Definition ALT_BN128_ADD_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x07"
     ],
@@ -97,7 +99,7 @@ Definition ALT_BN128_MUL_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x08"
     ],
@@ -107,7 +109,7 @@ Definition ALT_BN128_PAIRING_CHECK_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition BLAKE2F_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x09"
     ],
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/alt_bn128.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/alt_bn128.v
index 69c7cc0..4f8ddae 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/alt_bn128.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/alt_bn128.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.alt_bn128".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.alt_bn128".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -55,8 +57,9 @@ Axiom ethereum_shanghai_vm_exceptions_imports_OutOfGasError :
   IsImported globals "ethereum.shanghai.vm.exceptions" "OutOfGasError".
 
 Definition alt_bn128_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 addition precompiled contract.
 
@@ -67,14 +70,14 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 150
         ],
@@ -86,18 +89,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -110,9 +113,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -120,18 +123,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -144,9 +147,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -154,18 +157,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 64
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -178,9 +181,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x1_bytes" |)
+          M.get_name (| globals, locals_stack, "x1_bytes" |)
         ],
         make_dict []
       |)
@@ -188,18 +191,18 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 96
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -212,28 +215,28 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y1_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y1_bytes" |)
+          M.get_name (| globals, locals_stack, "y1_bytes" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |); M.get_name (| globals, "x1_value" |); M.get_name (| globals, "y1_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |); M.get_name (| globals, locals_stack, "x1_value" |); M.get_name (| globals, locals_stack, "y1_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -249,20 +252,20 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       BinOp.add (|
-        M.get_name (| globals, "p0" |),
-        M.get_name (| globals, "p1" |)
+        M.get_name (| globals, locals_stack, "p0" |),
+        M.get_name (| globals, locals_stack, "p1" |)
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -271,8 +274,9 @@ Definition alt_bn128_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 multiplication precompiled contract.
 
@@ -283,14 +287,14 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 6000
         ],
@@ -302,18 +306,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -326,9 +330,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "x0_bytes" |)
+          M.get_name (| globals, locals_stack, "x0_bytes" |)
         ],
         make_dict []
       |)
@@ -336,18 +340,18 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -360,9 +364,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y0_value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "y0_bytes" |)
+          M.get_name (| globals, locals_stack, "y0_bytes" |)
         ],
         make_dict []
       |)
@@ -370,21 +374,21 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "n" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -399,19 +403,19 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
-        make_tuple [ M.get_name (| globals, "x0_value" |); M.get_name (| globals, "y0_value" |) ],
+        M.get_name (| globals, locals_stack, "i" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "x0_value" |); M.get_name (| globals, locals_stack, "y0_value" |) ],
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.gt_e (|
-                M.get_name (| globals, "i" |),
-                M.get_name (| globals, "ALT_BN128_PRIME" |)
+                M.get_name (| globals, locals_stack, "i" |),
+                M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
               |),
             (* then *)
             ltac:(M.monadic (
-              let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+              let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
               M.pure Constant.None_
             (* else *)
             )), ltac:(M.monadic (
@@ -427,23 +431,23 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "p" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "p0" |), "mul_by" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "p0" |), "mul_by" |),
         make_list [
-          M.get_name (| globals, "n" |)
+          M.get_name (| globals, locals_stack, "n" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       BinOp.add (|
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "x" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "x" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "p" |), "y" |), "to_be_bytes32" |),
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "p" |), "y" |), "to_be_bytes32" |),
           make_list [],
           make_dict []
         |)
@@ -452,8 +456,9 @@ Definition alt_bn128_mul : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     The ALT_BN128 pairing check precompiled contract.
 
@@ -464,23 +469,23 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.mult (|
               Constant.int 34000,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |),
@@ -501,9 +506,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         Compare.not_eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "data" |)
+                M.get_name (| globals, locals_stack, "data" |)
               ],
               make_dict []
             |),
@@ -513,7 +518,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -522,7 +527,7 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
         make_list [
           Constant.int 1
         ],
@@ -531,15 +536,15 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             ],
             make_dict []
           |),
@@ -555,9 +560,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "j" |),
+              M.get_name (| globals, locals_stack, "j" |),
               M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 6
       ],
@@ -567,29 +572,29 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "value" ,
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                     make_list [
                       M.slice (|
-                        M.get_name (| globals, "data" |),
+                        M.get_name (| globals, locals_stack, "data" |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
-                            M.get_name (| globals, "j" |)
+                            M.get_name (| globals, locals_stack, "j" |)
                           |)
                         |),
                         BinOp.add (|
                           BinOp.mult (|
-                            M.get_name (| globals, "i" |),
+                            M.get_name (| globals, locals_stack, "i" |),
                             Constant.int 192
                           |),
                           BinOp.mult (|
                             Constant.int 32,
                             BinOp.add (|
-                              M.get_name (| globals, "j" |),
+                              M.get_name (| globals, locals_stack, "j" |),
                               Constant.int 1
                             |)
                           |)
@@ -604,24 +609,24 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     Compare.gt_e (|
-                      M.get_name (| globals, "value" |),
-                      M.get_name (| globals, "ALT_BN128_PRIME" |)
+                      M.get_name (| globals, locals_stack, "value" |),
+                      M.get_name (| globals, locals_stack, "ALT_BN128_PRIME" |)
                     |),
                   (* then *)
                   ltac:(M.monadic (
-                    let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+                    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
                     M.pure Constant.None_
                   (* else *)
                   )), ltac:(M.monadic (
                     M.pure Constant.None_
                   )) |) in
                 let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "values" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "values" |), "append" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "int" |),
+        M.get_name (| globals, locals_stack, "int" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -636,44 +641,44 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
           |) in
 (* At stmt: unsupported node type: Try *)
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "p" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "p" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "q" |), "mul_by" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "q" |), "mul_by" |),
           make_list [
-            M.get_name (| globals, "ALT_BN128_CURVE_ORDER" |)
+            M.get_name (| globals, locals_stack, "ALT_BN128_CURVE_ORDER" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "OutOfGasError" |)
+      M.get_name (| globals, locals_stack, "OutOfGasError" |)
     ],
     make_dict []
   |) in
@@ -682,18 +687,18 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.and (|
                 Compare.not_eq (|
-                  M.get_name (| globals, "p" |),
+                  M.get_name (| globals, locals_stack, "p" |),
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "BNP" |), "point_at_infinity" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "BNP" |), "point_at_infinity" |),
                     make_list [],
                     make_dict []
                   |)
                 |),
                 ltac:(M.monadic (
                   Compare.not_eq (|
-                    M.get_name (| globals, "q" |),
+                    M.get_name (| globals, locals_stack, "q" |),
                     M.call (|
-                      M.get_field (| M.get_name (| globals, "BNP2" |), "point_at_infinity" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "BNP2" |), "point_at_infinity" |),
                       make_list [],
                       make_dict []
                     |)
@@ -705,12 +710,12 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "result" ,
                 BinOp.mult (|
-                  M.get_name (| globals, "result" |),
+                  M.get_name (| globals, locals_stack, "result" |),
                   M.call (|
-                    M.get_name (| globals, "pairing" |),
+                    M.get_name (| globals, locals_stack, "pairing" |),
                     make_list [
-                      M.get_name (| globals, "q" |);
-                      M.get_name (| globals, "p" |)
+                      M.get_name (| globals, locals_stack, "q" |);
+                      M.get_name (| globals, locals_stack, "p" |)
                     ],
                     make_dict []
                   |)
@@ -731,9 +736,9 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "result" |),
+          M.get_name (| globals, locals_stack, "result" |),
           M.call (|
-            M.get_field (| M.get_name (| globals, "BNF12" |), "from_int" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "BNF12" |), "from_int" |),
             make_list [
               Constant.int 1
             ],
@@ -743,10 +748,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -760,10 +765,10 @@ Definition alt_bn128_pairing_check : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 0
               ],
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/blake2f.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/blake2f.v
index 1bef272..cbbac2e 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/blake2f.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/blake2f.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.blake2f".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.blake2f".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -35,8 +37,9 @@ Axiom ethereum_shanghai_vm_exceptions_imports_InvalidParameter :
   IsImported globals "ethereum.shanghai.vm.exceptions" "InvalidParameter".
 
 Definition blake2f : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the Blake2 hash to output.
 
@@ -47,79 +50,79 @@ Definition blake2f : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |),
         Constant.int 213
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "blake2b" ,
       M.call (|
-        M.get_name (| globals, "Blake2b" |),
+        M.get_name (| globals, locals_stack, "Blake2b" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "rounds" |); M.get_name (| globals, "h" |); M.get_name (| globals, "m" |); M.get_name (| globals, "t_0" |); M.get_name (| globals, "t_1" |); M.get_name (| globals, "f" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "rounds" |); M.get_name (| globals, locals_stack, "h" |); M.get_name (| globals, locals_stack, "m" |); M.get_name (| globals, locals_stack, "t_0" |); M.get_name (| globals, locals_stack, "t_1" |); M.get_name (| globals, locals_stack, "f" |) ],
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "get_blake2_parameters" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "get_blake2_parameters" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.mult (|
-        M.get_name (| globals, "GAS_BLAKE2_PER_ROUND" |),
-        M.get_name (| globals, "rounds" |)
+        M.get_name (| globals, locals_stack, "GAS_BLAKE2_PER_ROUND" |),
+        M.get_name (| globals, locals_stack, "rounds" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_name (| globals, "f" |),
+        M.get_name (| globals, locals_stack, "f" |),
         make_list [
           Constant.int 0;
           Constant.int 1
         ]
       |);
-      M.get_name (| globals, "InvalidParameter" |)
+      M.get_name (| globals, locals_stack, "InvalidParameter" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_field (| M.get_name (| globals, "blake2b" |), "compress" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "blake2b" |), "compress" |),
         make_list [
-          M.get_name (| globals, "rounds" |);
-          M.get_name (| globals, "h" |);
-          M.get_name (| globals, "m" |);
-          M.get_name (| globals, "t_0" |);
-          M.get_name (| globals, "t_1" |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "rounds" |);
+          M.get_name (| globals, locals_stack, "h" |);
+          M.get_name (| globals, locals_stack, "m" |);
+          M.get_name (| globals, locals_stack, "t_0" |);
+          M.get_name (| globals, locals_stack, "t_1" |);
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ecrecover.v
index ac4b74e..37e81ce 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_shanghai_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.shanghai.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/identity.v
index 554096f..eedb8c2 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_shanghai_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.shanghai.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/mapping.v
index 9fd8e82..a6e0686 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/modexp.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/modexp.v
index 9c94a82..8749a71 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/modexp.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/modexp.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.modexp".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.modexp".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,34 +40,35 @@ Definition GQUADDIVISOR : Value.t := M.run ltac:(M.monadic (
 )).
 
 Definition modexp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates `(base**exp) % modulus` for arbitrary sized `base`, `exp` and.
     `modulus`. The return value is the same length as the modulus.
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "base_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -81,21 +84,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -111,21 +114,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_length" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -142,36 +145,36 @@ Definition modexp : Value.t -> Value.t -> M :=
       "exp_start" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "U256" |),
+          M.get_name (| globals, locals_stack, "U256" |),
           make_list [
             Constant.int 96
           ],
           make_dict []
         |),
-        M.get_name (| globals, "base_length" |)
+        M.get_name (| globals, locals_stack, "base_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "exp_head" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
               M.call (|
-                M.get_name (| globals, "min" |),
+                M.get_name (| globals, locals_stack, "min" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 32
                     ],
                     make_dict []
                   |);
-                  M.get_name (| globals, "exp_length" |)
+                  M.get_name (| globals, locals_stack, "exp_length" |)
                 ],
                 make_dict []
               |)
@@ -183,16 +186,16 @@ Definition modexp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "gas_cost" |),
+        M.get_name (| globals, locals_stack, "gas_cost" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |);
-          M.get_name (| globals, "exp_length" |);
-          M.get_name (| globals, "exp_head" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |);
+          M.get_name (| globals, locals_stack, "exp_length" |);
+          M.get_name (| globals, locals_stack, "exp_head" |)
         ],
         make_dict []
       |)
@@ -204,12 +207,12 @@ Definition modexp : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "base_length" |),
+            M.get_name (| globals, locals_stack, "base_length" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "modulus_length" |),
+              M.get_name (| globals, locals_stack, "modulus_length" |),
               Constant.int 0
             |)
           ))
@@ -217,9 +220,9 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [],
             make_dict []
           |)
@@ -235,20 +238,20 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |)
@@ -259,14 +262,14 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exp" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "exp_start" |);
-              M.get_name (| globals, "exp_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "exp_start" |);
+              M.get_name (| globals, locals_stack, "exp_length" |)
             ],
             make_dict []
           |)
@@ -277,21 +280,21 @@ Definition modexp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "modulus_start" ,
       BinOp.add (|
-        M.get_name (| globals, "exp_start" |),
-        M.get_name (| globals, "exp_length" |)
+        M.get_name (| globals, locals_stack, "exp_start" |),
+        M.get_name (| globals, locals_stack, "exp_length" |)
       |)
     |) in
     let _ := M.assign_local (|
       "modulus" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
-              M.get_name (| globals, "modulus_start" |);
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "data" |);
+              M.get_name (| globals, locals_stack, "modulus_start" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -303,39 +306,39 @@ Definition modexp : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "modulus" |),
+          M.get_name (| globals, locals_stack, "modulus" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "Bytes" |),
+              M.get_name (| globals, locals_stack, "Bytes" |),
               make_list [
                 Constant.bytes "00"
               ],
               make_dict []
             |),
-            M.get_name (| globals, "modulus_length" |)
+            M.get_name (| globals, locals_stack, "modulus_length" |)
           |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
           M.call (|
             M.get_field (| M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "pow" |),
+                  M.get_name (| globals, locals_stack, "pow" |),
                   make_list [
-                    M.get_name (| globals, "base" |);
-                    M.get_name (| globals, "exp" |);
-                    M.get_name (| globals, "modulus" |)
+                    M.get_name (| globals, locals_stack, "base" |);
+                    M.get_name (| globals, locals_stack, "exp" |);
+                    M.get_name (| globals, locals_stack, "modulus" |)
                   ],
                   make_dict []
                 |)
@@ -343,7 +346,7 @@ Definition modexp : Value.t -> Value.t -> M :=
               make_dict []
             |), "to_bytes" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |);
+              M.get_name (| globals, locals_stack, "modulus_length" |);
               Constant.str "big"
             ],
             make_dict []
@@ -354,8 +357,9 @@ Definition modexp : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition complexity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Estimate the complexity of performing a modular exponentiation.
 
@@ -377,19 +381,19 @@ Definition complexity : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_length" ,
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "base_length" |)
+              M.get_name (| globals, locals_stack, "base_length" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "modulus_length" |)
+              M.get_name (| globals, locals_stack, "modulus_length" |)
             ],
             make_dict []
           |)
@@ -401,7 +405,7 @@ Definition complexity : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "max_length" |),
+          M.get_name (| globals, locals_stack, "max_length" |),
           Constant.int 7
         |),
         Constant.int 8
@@ -409,15 +413,16 @@ Definition complexity : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.pow (|
-        M.get_name (| globals, "words" |),
+        M.get_name (| globals, locals_stack, "words" |),
         Constant.int 2
       |)
     |) in
     M.pure Constant.None_)).
 
 Definition iterations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the number of iterations required to perform a modular
     exponentiation.
@@ -443,12 +448,12 @@ Definition iterations : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.lt_e (|
-            M.get_name (| globals, "exponent_length" |),
+            M.get_name (| globals, locals_stack, "exponent_length" |),
             Constant.int 32
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "exponent_head" |),
+              M.get_name (| globals, locals_stack, "exponent_head" |),
               Constant.int 0
             |)
           ))
@@ -458,7 +463,7 @@ Definition iterations : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "count" ,
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -472,7 +477,7 @@ Definition iterations : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.lt_e (|
-              M.get_name (| globals, "exponent_length" |),
+              M.get_name (| globals, locals_stack, "exponent_length" |),
               Constant.int 32
             |),
           (* then *)
@@ -480,10 +485,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bit_length" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -495,7 +500,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bit_length" |),
+                  M.get_name (| globals, locals_stack, "bit_length" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -512,7 +517,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               )) |) in
             let _ := M.assign_local (|
               "count" ,
-              M.get_name (| globals, "bit_length" |)
+              M.get_name (| globals, locals_stack, "bit_length" |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -523,9 +528,9 @@ Definition iterations : Value.t -> Value.t -> M :=
                 Constant.int 8,
                 BinOp.sub (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "exponent_length" |)
+                      M.get_name (| globals, locals_stack, "exponent_length" |)
                     ],
                     make_dict []
                   |),
@@ -536,10 +541,10 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "bits_part" ,
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "exponent_head" |), "bit_length" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "exponent_head" |), "bit_length" |),
                     make_list [],
                     make_dict []
                   |)
@@ -551,7 +556,7 @@ Definition iterations : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.gt (|
-                  M.get_name (| globals, "bits_part" |),
+                  M.get_name (| globals, locals_stack, "bits_part" |),
                   Constant.int 0
                 |),
               (* then *)
@@ -569,8 +574,8 @@ Definition iterations : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "count" ,
               BinOp.add (|
-                M.get_name (| globals, "length_part" |),
-                M.get_name (| globals, "bits_part" |)
+                M.get_name (| globals, locals_stack, "length_part" |),
+                M.get_name (| globals, locals_stack, "bits_part" |)
               |)
             |) in
             M.pure Constant.None_
@@ -579,11 +584,11 @@ Definition iterations : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
-          M.get_name (| globals, "count" |);
+          M.get_name (| globals, locals_stack, "count" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 1
             ],
@@ -596,8 +601,9 @@ Definition iterations : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "base_length"; "modulus_length"; "exponent_length"; "exponent_head" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the gas cost of performing a modular exponentiation.
 
@@ -626,10 +632,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "multiplication_complexity" ,
       M.call (|
-        M.get_name (| globals, "complexity" |),
+        M.get_name (| globals, locals_stack, "complexity" |),
         make_list [
-          M.get_name (| globals, "base_length" |);
-          M.get_name (| globals, "modulus_length" |)
+          M.get_name (| globals, locals_stack, "base_length" |);
+          M.get_name (| globals, locals_stack, "modulus_length" |)
         ],
         make_dict []
       |)
@@ -637,10 +643,10 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "iteration_count" ,
       M.call (|
-        M.get_name (| globals, "iterations" |),
+        M.get_name (| globals, locals_stack, "iterations" |),
         make_list [
-          M.get_name (| globals, "exponent_length" |);
-          M.get_name (| globals, "exponent_head" |)
+          M.get_name (| globals, locals_stack, "exponent_length" |);
+          M.get_name (| globals, locals_stack, "exponent_head" |)
         ],
         make_dict []
       |)
@@ -648,27 +654,27 @@ Definition gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "multiplication_complexity" |),
-        M.get_name (| globals, "iteration_count" |)
+        M.get_name (| globals, locals_stack, "multiplication_complexity" |),
+        M.get_name (| globals, locals_stack, "iteration_count" |)
       |)
     |) in
     let _ := M.assign_op_local (|
       BinOp.floor_div,
       "cost",
-      M.get_name (| globals, "GQUADDIVISOR" |)
+      M.get_name (| globals, locals_stack, "GQUADDIVISOR" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "max" |),
+        M.get_name (| globals, locals_stack, "max" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 200
             ],
             make_dict []
           |);
-          M.get_name (| globals, "cost" |)
+          M.get_name (| globals, locals_stack, "cost" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ripemd160.v
index 9ca951c..5ba441d 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_shanghai_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.shanghai.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/sha256.v
index d8d222a..206c822 100644
--- a/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/shanghai/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.shanghai.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_shanghai_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.shanghai.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/shanghai/vm/runtime.v b/CoqOfPython/ethereum/shanghai/vm/runtime.v
index 44bf9bf..e5e7231 100644
--- a/CoqOfPython/ethereum/shanghai/vm/runtime.v
+++ b/CoqOfPython/ethereum/shanghai/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.runtime".
+Definition globals : Globals.t := "ethereum.shanghai.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_shanghai_vm_instructions_imports_Ops :
   IsImported globals "ethereum.shanghai.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/shanghai/vm/stack.v b/CoqOfPython/ethereum/shanghai/vm/stack.v
index cbab960..a9b9678 100644
--- a/CoqOfPython/ethereum/shanghai/vm/stack.v
+++ b/CoqOfPython/ethereum/shanghai/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.shanghai.vm.stack".
+Definition globals : Globals.t := "ethereum.shanghai.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_shanghai_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.shanghai.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/simulations/base_types.v b/CoqOfPython/ethereum/simulations/base_types.v
new file mode 100644
index 0000000..864d5b2
--- /dev/null
+++ b/CoqOfPython/ethereum/simulations/base_types.v
@@ -0,0 +1,208 @@
+Require Import CoqOfPython.CoqOfPython.
+Require Import simulations.CoqOfPython.
+Require Import simulations.builtins.
+
+Import simulations.CoqOfPython.Notations.
+
+Definition globals : Globals.t := "ethereum.base_types".
+
+Definition U255_CEIL_VALUE : Z := 2^255.
+
+Definition U256_CEIL_VALUE : Z := 2^256.
+
+Module Uint.
+  Inductive t : Set :=
+  | Make (value : Z).
+
+  Definition get (value : t) : Z :=
+    match value with
+    | Make value => value
+    end.
+
+  Definition __add__ (self right_ : t) : t :=
+    Make (get self + get right_).
+End Uint.
+
+Module FixedUint.
+  Record t : Set := {
+    MAX_VALUE : Z;
+    value : Z;
+  }.
+
+  Definition __add__ (self right_ : t) : M? Exception.t t :=
+    let result := (self.(value) + right_.(value))%Z in
+    if result >? self.(MAX_VALUE) then
+      Error.raise (Exception.ArithmeticError ArithmeticError.OverflowError)
+    else
+      return? {|
+        MAX_VALUE := self.(MAX_VALUE);
+        value := result;
+      |}.
+
+  Definition wrapping_add (self right_ : t) : t :=
+    let sum := (self.(value) + right_.(value))%Z in
+    {|
+      MAX_VALUE := self.(MAX_VALUE);
+      value := Z.modulo sum self.(MAX_VALUE);
+    |}.
+End FixedUint.
+
+Module U256.
+  Inductive t : Set :=
+  | Make (value : FixedUint.t).
+
+  Definition of_Z (value : Z) : t :=
+    Make {|
+      FixedUint.MAX_VALUE := 2^256 - 1;
+      FixedUint.value := value;
+    |}.
+
+  Definition get (value : t) : FixedUint.t :=
+    let 'Make value := value in
+    value.
+
+  Definition to_Z (value : t) : Z :=
+    FixedUint.value (get value).
+
+  Definition to_value (value : t) : Value.t :=
+    Value.Make globals "U256" (Pointer.Imm (Object.wrapper (Data.Integer (to_Z value)))).
+
+  Definition __add__ (self right_ : t) : M? Exception.t t :=
+    let? result := FixedUint.__add__ (get self) (get right_) in
+    return? (Make result).
+
+  Definition wrapping_add (self right_ : t) : t :=
+    Make (FixedUint.wrapping_add (get self) (get right_)).
+End U256.
+
+Module U32.
+  Inductive t : Set :=
+  | Make (value : FixedUint.t).
+
+  Definition of_Z (value : Z) : t :=
+    Make {|
+      FixedUint.MAX_VALUE := 2^32 - 1;
+      FixedUint.value := value;
+    |}.
+
+  Definition get (value : t) : FixedUint.t :=
+    match value with
+    | Make value => value
+    end.
+End U32.
+
+Module U64.
+  Inductive t : Set :=
+  | Make (value : FixedUint.t).
+
+  Definition of_Z (value : Z) : t :=
+    Make {|
+      FixedUint.MAX_VALUE := 2^64 - 1;
+      FixedUint.value := value;
+    |}.
+
+  Definition get (value : t) : FixedUint.t :=
+    match value with
+    | Make value => value
+    end.
+End U64.
+
+Module FixedBytes.
+  Inductive t : Set :=
+  | Make (bytes : list ascii).
+
+  Definition get (bytes : t) : list ascii :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End FixedBytes.
+
+Module Bytes0.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes0.
+
+Module Bytes4.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes4.
+
+Module Bytes8.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes8.
+
+Module Bytes20.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes20.
+
+Module Bytes32.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes32.
+
+Module Bytes48.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes48.
+
+Module Bytes64.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes64.
+
+Module Bytes256.
+  Inductive t : Set :=
+  | Make (bytes : FixedBytes.t).
+
+  Definition get (bytes : t) : FixedBytes.t :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes256.
+
+Module Bytes.
+  Inductive t : Set :=
+  | Make (bytes : list ascii).
+
+  Definition get (bytes : t) : list ascii :=
+    match bytes with
+    | Make bytes => bytes
+    end.
+End Bytes.
diff --git a/CoqOfPython/ethereum/simulations/exceptions.v b/CoqOfPython/ethereum/simulations/exceptions.v
new file mode 100644
index 0000000..d5e0926
--- /dev/null
+++ b/CoqOfPython/ethereum/simulations/exceptions.v
@@ -0,0 +1,7 @@
+Require Import CoqOfPython.CoqOfPython.
+Require ethereum.paris.vm.simulations.exceptions.
+
+Module EthereumException.
+  Inductive t : Set :=
+  | ExceptionalHalt (exn : exceptions.ExceptionalHalt.t).
+End EthereumException.
diff --git a/CoqOfPython/ethereum/spurious_dragon/__init__.v b/CoqOfPython/ethereum/spurious_dragon/__init__.v
index 1f1b6ac..43e92cd 100644
--- a/CoqOfPython/ethereum/spurious_dragon/__init__.v
+++ b/CoqOfPython/ethereum/spurious_dragon/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.__init__".
+Definition globals : Globals.t := "ethereum.spurious_dragon.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -16,7 +18,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 2675000
     ],
diff --git a/CoqOfPython/ethereum/spurious_dragon/blocks.v b/CoqOfPython/ethereum/spurious_dragon/blocks.v
index 1057a2e..b0c41a7 100644
--- a/CoqOfPython/ethereum/spurious_dragon/blocks.v
+++ b/CoqOfPython/ethereum/spurious_dragon/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.blocks".
+Definition globals : Globals.t := "ethereum.spurious_dragon.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/spurious_dragon/bloom.v b/CoqOfPython/ethereum/spurious_dragon/bloom.v
index ba09205..3d5bc38 100644
--- a/CoqOfPython/ethereum/spurious_dragon/bloom.v
+++ b/CoqOfPython/ethereum/spurious_dragon/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.bloom".
+Definition globals : Globals.t := "ethereum.spurious_dragon.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_spurious_dragon_fork_types_imports_Bloom :
   IsImported globals "ethereum.spurious_dragon.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/fork.v b/CoqOfPython/ethereum/spurious_dragon/fork.v
index db39a8f..a7f269c 100644
--- a/CoqOfPython/ethereum/spurious_dragon/fork.v
+++ b/CoqOfPython/ethereum/spurious_dragon/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.fork".
+Definition globals : Globals.t := "ethereum.spurious_dragon.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -136,7 +138,7 @@ Axiom ethereum_spurious_dragon_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 5,
@@ -160,7 +162,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -183,8 +185,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -204,13 +207,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -233,7 +237,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -244,9 +248,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -268,17 +272,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -291,13 +295,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -308,20 +312,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -346,111 +351,111 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-          M.get_field (| M.get_name (| globals, "chain" |), "chain_id" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "chain_id" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -459,9 +464,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -470,9 +475,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -486,8 +491,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -506,95 +512,95 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -603,28 +609,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -650,26 +657,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -677,8 +684,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -696,9 +704,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -706,25 +714,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -733,41 +741,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -791,35 +800,36 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "chain_id" |);
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "chain_id" |);
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -843,13 +853,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -864,8 +874,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -908,51 +919,51 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |);
-                M.get_name (| globals, "chain_id" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |);
+                M.get_name (| globals, locals_stack, "chain_id" |)
               ],
               make_dict []
             |)
@@ -960,18 +971,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -979,55 +990,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
+                M.get_name (| globals, locals_stack, "tx" |);
                 M.call (|
-                  M.get_name (| globals, "state_root" |),
+                  M.get_name (| globals, locals_stack, "state_root" |),
                   make_list [
-                    M.get_name (| globals, "state" |)
+                    M.get_name (| globals, locals_stack, "state" |)
                   ],
                   make_dict []
                 |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1036,56 +1047,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1096,8 +1107,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1122,27 +1134,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1151,9 +1163,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1171,46 +1183,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1221,19 +1233,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1242,23 +1254,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1266,16 +1278,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1289,13 +1301,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1310,11 +1322,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1322,88 +1334,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1416,8 +1428,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1446,44 +1459,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1495,19 +1508,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1520,8 +1533,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1549,30 +1563,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1580,98 +1594,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1679,10 +1693,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1690,20 +1704,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1712,10 +1726,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1723,41 +1737,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1765,31 +1779,31 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.not_eq (|
-          M.get_name (| globals, "coinbase_balance_after_mining_fee" |),
+          M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
@@ -1800,20 +1814,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
     ],
     make_dict []
   |) in
@@ -1826,14 +1840,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1845,27 +1859,27 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "touched_accounts" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "touched_accounts" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "account_exists_and_is_empty" |),
+                M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1881,13 +1895,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1916,17 +1931,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1941,8 +1956,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1971,14 +1987,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1986,7 +2002,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1994,7 +2010,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -2008,9 +2024,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -2021,7 +2037,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -2034,14 +2050,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -2050,8 +2066,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain_id"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain_id"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -2074,47 +2091,47 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -2123,12 +2140,12 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -2138,18 +2155,18 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
-                M.get_name (| globals, "v" |),
+                M.get_name (| globals, locals_stack, "v" |),
                 Constant.int 27
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_pre155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_pre155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |)
+                  M.get_name (| globals, locals_stack, "tx" |)
                 ],
                 make_dict []
               |)
@@ -2161,58 +2178,58 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           BinOp.add (|
             Constant.int 35,
             BinOp.mult (|
-              M.get_name (| globals, "chain_id" |),
+              M.get_name (| globals, locals_stack, "chain_id" |),
               Constant.int 2
             |)
           |)
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             BinOp.add (|
               Constant.int 36,
               BinOp.mult (|
-                M.get_name (| globals, "chain_id" |),
+                M.get_name (| globals, locals_stack, "chain_id" |),
                 Constant.int 2
               |)
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
         let _ := M.assign_local (|
           "public_key" ,
           M.call (|
-            M.get_name (| globals, "secp256k1_recover" |),
+            M.get_name (| globals, locals_stack, "secp256k1_recover" |),
             make_list [
-              M.get_name (| globals, "r" |);
-              M.get_name (| globals, "s" |);
+              M.get_name (| globals, locals_stack, "r" |);
+              M.get_name (| globals, locals_stack, "s" |);
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "v" |),
+                  M.get_name (| globals, locals_stack, "v" |),
                   Constant.int 35
                 |),
                 BinOp.mult (|
-                  M.get_name (| globals, "chain_id" |),
+                  M.get_name (| globals, locals_stack, "chain_id" |),
                   Constant.int 2
                 |)
               |);
               M.call (|
-                M.get_name (| globals, "signing_hash_155" |),
+                M.get_name (| globals, locals_stack, "signing_hash_155" |),
                 make_list [
-                  M.get_name (| globals, "tx" |);
-                  M.get_name (| globals, "chain_id" |)
+                  M.get_name (| globals, locals_stack, "tx" |);
+                  M.get_name (| globals, locals_stack, "chain_id" |)
                 ],
                 make_dict []
               |)
@@ -2224,13 +2241,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2245,8 +2262,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a legacy (pre EIP 155) signature.
 
@@ -2262,12 +2280,12 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2278,8 +2296,9 @@ Definition signing_hash_pre155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash_155 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "chain_id" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "chain_id" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in a EIP 155 signature.
 
@@ -2297,19 +2316,19 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |); M.get_name (| globals, "chain_id" |); M.call (|
-                M.get_name (| globals, "Uint" |),
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |); M.get_name (| globals, locals_stack, "chain_id" |); M.call (|
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
                 make_dict []
               |); M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -2325,8 +2344,9 @@ Definition signing_hash_155 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2360,12 +2380,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2376,8 +2396,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2408,18 +2429,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2436,10 +2457,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2456,8 +2477,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2475,8 +2496,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2518,26 +2540,26 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
               Constant.int 1,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2555,13 +2577,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2569,9 +2591,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.sub (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |),
@@ -2584,7 +2606,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2594,7 +2616,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2604,13 +2626,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/fork_types.v b/CoqOfPython/ethereum/spurious_dragon/fork_types.v
index 92672ad..a204fad 100644
--- a/CoqOfPython/ethereum/spurious_dragon/fork_types.v
+++ b/CoqOfPython/ethereum/spurious_dragon/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.fork_types".
+Definition globals : Globals.t := "ethereum.spurious_dragon.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/spurious_dragon/state.v b/CoqOfPython/ethereum/spurious_dragon/state.v
index d7957d0..1c27206 100644
--- a/CoqOfPython/ethereum/spurious_dragon/state.v
+++ b/CoqOfPython/ethereum/spurious_dragon/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.state".
+Definition globals : Globals.t := "ethereum.spurious_dragon.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,8 +710,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has zero nonce, empty code and zero balance.
 
@@ -714,10 +732,10 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -725,9 +743,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -737,12 +755,12 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "code" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
               Constant.bytes ""
             |),
             ltac:(M.monadic (
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                 Constant.int 0
               |)
             ))
@@ -753,8 +771,9 @@ Definition is_account_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists and has zero nonce, empty code and zero
     balance.
@@ -775,10 +794,10 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -786,15 +805,15 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.and (|
         Compare.is_not (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
         ltac:(M.monadic (
           BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -804,12 +823,12 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -822,8 +841,9 @@ Definition account_exists_and_is_empty : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_account_alive : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check whether is an account is both in the state and non empty.
 
@@ -842,10 +862,10 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -854,7 +874,7 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "account" |),
+          M.get_name (| globals, locals_stack, "account" |),
           Constant.None_
         |),
       (* then *)
@@ -868,9 +888,9 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           UnOp.not (| BoolOp.and (|
             Compare.eq (|
-              M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -880,12 +900,12 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
             ltac:(M.monadic (
               BoolOp.and (|
                 Compare.eq (|
-                  M.get_field (| M.get_name (| globals, "account" |), "code" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
                   Constant.bytes ""
                 |),
                 ltac:(M.monadic (
                   Compare.eq (|
-                    M.get_field (| M.get_name (| globals, "account" |), "balance" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "account" |), "balance" |),
                     Constant.int 0
                   |)
                 ))
@@ -898,28 +918,29 @@ Definition is_account_alive : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -929,36 +950,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -975,19 +998,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -1003,21 +1027,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -1029,8 +1053,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -1044,19 +1069,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -1073,19 +1099,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -1100,11 +1127,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/spurious_dragon/transactions.v b/CoqOfPython/ethereum/spurious_dragon/transactions.v
index d563ae6..d732447 100644
--- a/CoqOfPython/ethereum/spurious_dragon/transactions.v
+++ b/CoqOfPython/ethereum/spurious_dragon/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.transactions".
+Definition globals : Globals.t := "ethereum.spurious_dragon.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/spurious_dragon/trie.v b/CoqOfPython/ethereum/spurious_dragon/trie.v
index acd6b08..308456a 100644
--- a/CoqOfPython/ethereum/spurious_dragon/trie.v
+++ b/CoqOfPython/ethereum/spurious_dragon/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.trie".
+Definition globals : Globals.t := "ethereum.spurious_dragon.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_spurious_dragon_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/utils/__init__.v b/CoqOfPython/ethereum/spurious_dragon/utils/__init__.v
index 05c126f..fb47a7a 100644
--- a/CoqOfPython/ethereum/spurious_dragon/utils/__init__.v
+++ b/CoqOfPython/ethereum/spurious_dragon/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.utils.__init__".
+Definition globals : Globals.t := "ethereum.spurious_dragon.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/spurious_dragon/utils/address.v b/CoqOfPython/ethereum/spurious_dragon/utils/address.v
index a4a5c3d..cc80f3d 100644
--- a/CoqOfPython/ethereum/spurious_dragon/utils/address.v
+++ b/CoqOfPython/ethereum/spurious_dragon/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.utils.address".
+Definition globals : Globals.t := "ethereum.spurious_dragon.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_spurious_dragon_fork_types_imports_Address :
   IsImported globals "ethereum.spurious_dragon.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -56,11 +59,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -75,8 +78,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -96,14 +100,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -115,7 +119,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -124,9 +128,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -134,9 +138,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/utils/hexadecimal.v b/CoqOfPython/ethereum/spurious_dragon/utils/hexadecimal.v
index bbdbabf..9848a7b 100644
--- a/CoqOfPython/ethereum/spurious_dragon/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/spurious_dragon/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.spurious_dragon.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_spurious_dragon_fork_types_imports_Root :
   IsImported globals "ethereum.spurious_dragon.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/spurious_dragon/utils/message.v b/CoqOfPython/ethereum/spurious_dragon/utils/message.v
index a356277..9c1f9e7 100644
--- a/CoqOfPython/ethereum/spurious_dragon/utils/message.v
+++ b/CoqOfPython/ethereum/spurious_dragon/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.utils.message".
+Definition globals : Globals.t := "ethereum.spurious_dragon.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_spurious_dragon_utils_address_imports_compute_contract_address :
   IsImported globals "ethereum.spurious_dragon.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -82,10 +85,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -94,20 +97,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -121,7 +124,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -130,7 +133,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -139,10 +142,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -150,19 +153,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -171,14 +174,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -189,7 +192,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -201,7 +204,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/__init__.v b/CoqOfPython/ethereum/spurious_dragon/vm/__init__.v
index 9637d09..96afc79 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/__init__.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.__init__".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -93,8 +95,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -107,30 +110,30 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
     ],
     make_dict []
   |) in
@@ -138,19 +141,19 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -162,8 +165,9 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -178,15 +182,15 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |),
-          M.get_field (| M.get_name (| globals, "child_evm" |), "touched_accounts" |)
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "touched_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -199,8 +203,8 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |),
-          M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |),
+          M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -208,19 +212,19 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "RIPEMD160_ADDRESS" |)
+      M.get_name (| globals, locals_stack, "RIPEMD160_ADDRESS" |)
     ],
     make_dict []
   |) in
@@ -236,7 +240,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/exceptions.v b/CoqOfPython/ethereum/spurious_dragon/vm/exceptions.v
index 5caf2c5..324690f 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/exceptions.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.exceptions".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -69,22 +71,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/gas.v b/CoqOfPython/ethereum/spurious_dragon/vm/gas.v
index 6f64c28..9462610 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/gas.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.gas".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_spurious_dragon_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 50
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 400
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -455,8 +457,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -469,13 +472,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -486,22 +489,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -511,8 +514,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -532,9 +536,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -544,15 +548,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -561,16 +565,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -589,7 +594,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,12 +614,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -624,14 +629,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -645,9 +650,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -655,20 +660,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -681,8 +686,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -696,16 +701,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -713,9 +718,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -724,13 +729,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -740,10 +745,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -751,8 +756,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -783,13 +789,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -797,32 +803,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -836,18 +842,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -858,15 +864,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -875,8 +881,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -892,9 +899,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/__init__.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/__init__.v
index a4fd34b..e153214 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/arithmetic.v
index 2256f4d..1ba88bd 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/bitwise.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/bitwise.v
index fc29c9b..925d2d6 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/block.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/block.v
index d8850a8..4eaa164 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/comparison.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/comparison.v
index e7f431c..bc0bd53 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/control_flow.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/control_flow.v
index f96d87f..5673b3f 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/environment.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/environment.v
index 00c40fe..fff0fc8 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -60,8 +62,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -73,21 +76,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -96,14 +99,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -116,12 +120,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -130,42 +134,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -178,21 +183,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -201,14 +206,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -220,21 +226,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -243,14 +249,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -262,31 +269,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -300,30 +308,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -334,13 +342,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -349,14 +357,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -368,24 +377,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -397,14 +406,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -420,9 +430,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +440,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +450,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -451,12 +461,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -469,76 +479,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -550,24 +561,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -579,14 +590,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -602,9 +614,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -612,9 +624,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -622,9 +634,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -633,12 +645,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -651,76 +663,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -732,21 +745,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -755,14 +768,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -775,12 +789,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -789,26 +803,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -820,23 +834,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -849,12 +864,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -865,9 +880,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -875,9 +890,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -885,9 +900,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -896,12 +911,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -914,52 +929,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -967,27 +982,27 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/keccak.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/keccak.v
index b4aecb5..d650183 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/log.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/log.v
index db24bd8..5ac6e29 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_pop :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -66,9 +69,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -89,11 +92,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -102,9 +105,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -113,9 +116,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -128,74 +131,74 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -203,9 +206,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -213,9 +216,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -223,9 +226,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -233,9 +236,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/memory.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/memory.v
index a320784..fd7b476 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/stack.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/stack.v
index 4846fa5..89d8459 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_spurious_dragon_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.spurious_dragon.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/storage.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/storage.v
index 2c14d8c..adb9427 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,8 +44,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -58,9 +61,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -69,43 +72,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -119,9 +123,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -132,9 +136,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,11 +146,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -156,12 +160,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -170,14 +174,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -186,12 +190,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -200,8 +204,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -209,26 +213,26 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/system.v b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/system.v
index 1bb34af..0709924 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -90,8 +92,9 @@ Axiom ethereum_spurious_dragon_vm_stack_imports_push :
   IsImported globals "ethereum.spurious_dragon.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -104,9 +107,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -114,9 +117,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -124,9 +127,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -134,23 +137,23 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -158,12 +161,12 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -173,28 +176,28 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -202,14 +205,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -222,15 +225,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -246,10 +249,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -258,11 +261,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -273,8 +276,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -283,29 +286,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -320,27 +323,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -348,10 +351,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -359,23 +362,23 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -388,21 +391,21 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -417,14 +420,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -436,9 +440,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -446,9 +450,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -456,57 +460,58 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
@@ -516,24 +521,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -553,11 +558,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -565,10 +570,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -576,7 +581,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -584,10 +589,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -595,23 +600,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -624,19 +629,19 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -650,16 +655,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -671,14 +676,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -687,8 +692,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -700,12 +706,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -716,12 +722,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -732,9 +738,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -742,9 +748,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -752,9 +758,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -762,9 +768,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -772,9 +778,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -782,12 +788,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -799,15 +805,15 @@ Definition call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.eq (|
-            M.get_name (| globals, "value" |),
+            M.get_name (| globals, locals_stack, "value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             M.call (|
-              M.get_name (| globals, "is_account_alive" |),
+              M.get_name (| globals, locals_stack, "is_account_alive" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "to" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "to" |)
               ],
               make_dict []
             |)
@@ -816,7 +822,7 @@ Definition call : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -824,7 +830,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -832,13 +838,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -846,61 +852,61 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -909,17 +915,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -930,26 +936,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -957,14 +963,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -976,12 +983,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -992,12 +999,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1008,9 +1015,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1018,9 +1025,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1028,9 +1035,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1038,9 +1045,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1048,26 +1055,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1078,13 +1085,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1092,58 +1099,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1152,17 +1159,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1173,26 +1180,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1200,14 +1207,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1219,12 +1227,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1234,27 +1242,27 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
           UnOp.not (| M.call (|
-            M.get_name (| globals, "is_account_alive" |),
+            M.get_name (| globals, locals_stack, "is_account_alive" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_name (| globals, "beneficiary" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_name (| globals, locals_stack, "beneficiary" |)
             ],
             make_dict []
           |) |),
           ltac:(M.monadic (
             Compare.not_eq (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
                 ],
                 make_dict []
               |), "balance" |),
@@ -1267,7 +1275,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1276,33 +1284,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1314,15 +1322,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1330,20 +1338,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1351,33 +1359,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1387,9 +1395,9 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
@@ -1397,19 +1405,19 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "account_exists_and_is_empty" |),
+          M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
-      M.get_name (| globals, "beneficiary" |)
+      M.get_name (| globals, locals_stack, "beneficiary" |)
     ],
     make_dict []
   |) in
@@ -1419,15 +1427,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1439,12 +1448,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1455,12 +1464,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1471,9 +1480,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1481,9 +1490,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1491,9 +1500,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1501,9 +1510,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1511,12 +1520,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1525,68 +1534,68 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/interpreter.v b/CoqOfPython/ethereum/spurious_dragon/vm/interpreter.v
index e58aeba..06ea653 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/interpreter.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.interpreter".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -120,7 +122,7 @@ Axiom ethereum_spurious_dragon_vm_runtime_imports_get_valid_jump_destinations :
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -143,8 +145,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -166,9 +169,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -180,10 +183,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -191,44 +194,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -242,10 +245,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -258,10 +261,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -270,13 +273,13 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_exists_and_is_empty" |),
+              M.get_name (| globals, locals_stack, "account_exists_and_is_empty" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "env" |), "state" |);
+                M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "message" |), "target" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
                   ],
                   make_dict []
                 |)
@@ -286,12 +289,12 @@ Definition process_message_call : Value.t -> Value.t -> M :=
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |), "add" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "message" |), "target" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |)
         ],
         make_dict []
       |)
@@ -308,14 +311,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -323,7 +326,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "touched_accounts" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -331,7 +334,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -343,48 +346,48 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "touched_accounts" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "touched_accounts" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "touched_accounts" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -392,8 +395,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -410,35 +414,35 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -446,24 +450,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -471,22 +475,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -506,13 +511,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -524,17 +529,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -542,10 +547,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -553,12 +558,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -570,10 +575,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -581,13 +586,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -595,22 +600,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -628,14 +634,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -643,13 +649,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/memory.v b/CoqOfPython/ethereum/spurious_dragon/vm/memory.v
index b492085..6996c23 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/memory.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.memory".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/__init__.v
index 1d7b891..9865012 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ecrecover.v
index c1ae66e..4c51c76 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_spurious_dragon_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.spurious_dragon.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/identity.v
index c36d5ee..a610f97 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_spurious_dragon_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.spurious_dragon.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/mapping.v
index cba9815..775cb99 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ripemd160.v
index 029a148..518a15d 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_spurious_dragon_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.spurious_dragon.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/sha256.v
index c155fe7..19322f3 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_spurious_dragon_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.spurious_dragon.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/runtime.v b/CoqOfPython/ethereum/spurious_dragon/vm/runtime.v
index 9f6ecd8..bf9c04b 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/runtime.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.runtime".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_spurious_dragon_vm_instructions_imports_Ops :
   IsImported globals "ethereum.spurious_dragon.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/spurious_dragon/vm/stack.v b/CoqOfPython/ethereum/spurious_dragon/vm/stack.v
index b6fb48a..85f5983 100644
--- a/CoqOfPython/ethereum/spurious_dragon/vm/stack.v
+++ b/CoqOfPython/ethereum/spurious_dragon/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.spurious_dragon.vm.stack".
+Definition globals : Globals.t := "ethereum.spurious_dragon.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_spurious_dragon_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.spurious_dragon.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/__init__.v b/CoqOfPython/ethereum/tangerine_whistle/__init__.v
index fd543a7..b109ac7 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/__init__.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.__init__".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -15,7 +17,7 @@ Axiom ethereum_fork_criteria_imports_ByBlockNumber :
 
 Definition FORK_CRITERIA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "ByBlockNumber" |),
+    M.get_name (| globals, locals_stack, "ByBlockNumber" |),
     make_list [
       Constant.int 2463000
     ],
diff --git a/CoqOfPython/ethereum/tangerine_whistle/blocks.v b/CoqOfPython/ethereum/tangerine_whistle/blocks.v
index b921a0d..17115ef 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/blocks.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/blocks.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.blocks".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.blocks".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/tangerine_whistle/bloom.v b/CoqOfPython/ethereum/tangerine_whistle/bloom.v
index ccf56cd..263f8cb 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/bloom.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/bloom.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.bloom".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.bloom".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -37,8 +39,9 @@ Axiom ethereum_tangerine_whistle_fork_types_imports_Bloom :
   IsImported globals "ethereum.tangerine_whistle.fork_types" "Bloom".
 
 Definition add_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bloom"; "bloom_entry" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bloom"; "bloom_entry" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add a bloom entry to the bloom filter (`bloom`).
 
@@ -56,29 +59,29 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "bloom_entry" |)
+          M.get_name (| globals, locals_stack, "bloom_entry" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "idx" |),
+        M.get_name (| globals, locals_stack, "idx" |),
         make_tuple [ Constant.int 0; Constant.int 2; Constant.int 4 ],
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "bit_to_set" ,
             BinOp.bit_and (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
                 make_list [
                   M.slice (|
-                    M.get_name (| globals, "hash" |),
-                    M.get_name (| globals, "idx" |),
+                    M.get_name (| globals, locals_stack, "hash" |),
+                    M.get_name (| globals, locals_stack, "idx" |),
                     BinOp.add (|
-                      M.get_name (| globals, "idx" |),
+                      M.get_name (| globals, locals_stack, "idx" |),
                       Constant.int 2
                     |),
                     Constant.None_
@@ -93,13 +96,13 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
             "bit_index" ,
             BinOp.sub (|
               Constant.int 2047,
-              M.get_name (| globals, "bit_to_set" |)
+              M.get_name (| globals, locals_stack, "bit_to_set" |)
             |)
           |) in
           let _ := M.assign_local (|
             "byte_index" ,
             BinOp.floor_div (|
-              M.get_name (| globals, "bit_index" |),
+              M.get_name (| globals, locals_stack, "bit_index" |),
               Constant.int 8
             |)
           |) in
@@ -110,7 +113,7 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 7,
                 BinOp.mod_ (|
-                  M.get_name (| globals, "bit_index" |),
+                  M.get_name (| globals, locals_stack, "bit_index" |),
                   Constant.int 8
                 |)
               |)
@@ -118,15 +121,15 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "bloom" |),
-              M.get_name (| globals, "byte_index" |)
+              M.get_name (| globals, locals_stack, "bloom" |),
+              M.get_name (| globals, locals_stack, "byte_index" |)
             |),
             BinOp.bit_or (|
               M.get_subscript (|
-                M.get_name (| globals, "bloom" |),
-                M.get_name (| globals, "byte_index" |)
+                M.get_name (| globals, locals_stack, "bloom" |),
+                M.get_name (| globals, locals_stack, "byte_index" |)
               |),
-              M.get_name (| globals, "bit_value" |)
+              M.get_name (| globals, locals_stack, "bit_value" |)
             |)
           |) in
           M.pure Constant.None_
@@ -138,8 +141,9 @@ Definition add_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition logs_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the logs bloom from a list of log entries.
 
@@ -159,27 +163,27 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "log" |),
-        M.get_name (| globals, "logs" |),
+        M.get_name (| globals, locals_stack, "log" |),
+        M.get_name (| globals, locals_stack, "logs" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_field (| M.get_name (| globals, "log" |), "address" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "log" |), "address" |)
     ],
     make_dict []
   |) in
           let _ :=
             M.for_ (|
-              M.get_name (| globals, "topic" |),
-              M.get_field (| M.get_name (| globals, "log" |), "topics" |),
+              M.get_name (| globals, locals_stack, "topic" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "log" |), "topics" |),
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "add_to_bloom" |),
+    M.get_name (| globals, locals_stack, "add_to_bloom" |),
     make_list [
-      M.get_name (| globals, "bloom" |);
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "bloom" |);
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -197,9 +201,9 @@ Definition logs_bloom : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
-          M.get_name (| globals, "bloom" |)
+          M.get_name (| globals, locals_stack, "bloom" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/fork.v b/CoqOfPython/ethereum/tangerine_whistle/fork.v
index bc0e99d..3658e86 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/fork.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/fork.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.fork".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.fork".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -134,7 +136,7 @@ Axiom ethereum_tangerine_whistle_vm_interpreter_imports_process_message_call :
 
 Definition BLOCK_REWARD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       BinOp.mult (|
         Constant.int 5,
@@ -158,7 +160,7 @@ Definition GAS_LIMIT_MINIMUM : Value.t := M.run ltac:(M.monadic (
 
 Definition MINIMUM_DIFFICULTY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 131072
     ],
@@ -181,8 +183,9 @@ Definition BlockChain : Value.t :=
     ].
 
 Definition apply_fork : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "old" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "old" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Transforms the state from the previous hard fork (`old`) into the block
     chain object for this hard fork and returns it.
@@ -202,13 +205,14 @@ Definition apply_fork : Value.t -> Value.t -> M :=
         Upgraded block chain object for this hard fork.
     " in
     let _ := M.return_ (|
-      M.get_name (| globals, "old" |)
+      M.get_name (| globals, locals_stack, "old" |)
     |) in
     M.pure Constant.None_)).
 
 Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain the list of hashes of the previous 256 blocks in order of
     increasing block number.
@@ -231,7 +235,7 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "recent_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 255 |),
         Constant.None_,
         Constant.None_
@@ -242,9 +246,9 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "recent_blocks" |)
+              M.get_name (| globals, locals_stack, "recent_blocks" |)
             ],
             make_dict []
           |),
@@ -266,17 +270,17 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prev_block_hash" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "parent_hash" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "parent_hash" |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "prev_block_hash" |)
+      M.get_name (| globals, locals_stack, "prev_block_hash" |)
     ],
     make_dict []
   |) in
@@ -289,13 +293,13 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "most_recent_block_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               M.get_field (| M.get_subscript (|
-                M.get_name (| globals, "recent_blocks" |),
+                M.get_name (| globals, locals_stack, "recent_blocks" |),
                 UnOp.sub (| Constant.int 1 |)
               |), "header" |)
             ],
@@ -306,20 +310,21 @@ Definition get_last_256_block_hashes : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "recent_block_hashes" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "recent_block_hashes" |), "append" |),
     make_list [
-      M.get_name (| globals, "most_recent_block_hash" |)
+      M.get_name (| globals, locals_stack, "most_recent_block_hash" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "recent_block_hashes" |)
+      M.get_name (| globals, locals_stack, "recent_block_hashes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition state_transition : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "chain"; "block" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "chain"; "block" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Attempts to apply a block to an existing block chain.
 
@@ -344,110 +349,110 @@ Definition state_transition : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "parent_header" ,
       M.get_field (| M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| Constant.int 1 |)
       |), "header" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "parent_header" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "parent_header" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_ommers" |),
+    M.get_name (| globals, locals_stack, "validate_ommers" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "block" |), "ommers" |);
-      M.get_field (| M.get_name (| globals, "block" |), "header" |);
-      M.get_name (| globals, "chain" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |);
+      M.get_name (| globals, locals_stack, "chain" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "apply_body_output" ,
       M.call (|
-        M.get_name (| globals, "apply_body" |),
+        M.get_name (| globals, locals_stack, "apply_body" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "chain" |), "state" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "state" |);
           M.call (|
-            M.get_name (| globals, "get_last_256_block_hashes" |),
+            M.get_name (| globals, locals_stack, "get_last_256_block_hashes" |),
             make_list [
-              M.get_name (| globals, "chain" |)
+              M.get_name (| globals, locals_stack, "chain" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "coinbase" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "number" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_limit" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "timestamp" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "difficulty" |);
-          M.get_field (| M.get_name (| globals, "block" |), "transactions" |);
-          M.get_field (| M.get_name (| globals, "block" |), "ommers" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "coinbase" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "number" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_limit" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "timestamp" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "difficulty" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "transactions" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "block" |), "ommers" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_gas_used" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "gas_used" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_gas_used" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "gas_used" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "transactions_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "transactions_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "transactions_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "transactions_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "state_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "state_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "state_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "state_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "receipt_root" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "receipt_root" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "receipt_root" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "receipt_root" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "apply_body_output" |), "block_logs_bloom" |),
-        M.get_field (| M.get_field (| M.get_name (| globals, "block" |), "header" |), "bloom" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "apply_body_output" |), "block_logs_bloom" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "block" |), "header" |), "bloom" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "chain" |), "blocks" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |), "append" |),
     make_list [
-      M.get_name (| globals, "block" |)
+      M.get_name (| globals, locals_stack, "block" |)
     ],
     make_dict []
   |) in
@@ -456,9 +461,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |)
             ],
             make_dict []
           |),
@@ -467,9 +472,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign (|
-          M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
           M.slice (|
-            M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
             UnOp.sub (| Constant.int 255 |),
             Constant.None_,
             Constant.None_
@@ -483,8 +488,9 @@ Definition state_transition : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_header : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header"; "parent_header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header"; "parent_header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a block header.
 
@@ -503,95 +509,95 @@ Definition validate_header : Value.t -> Value.t -> M :=
         Parent Header of the header to check for correctness
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt (|
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |),
-        M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "number" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |),
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "parent_header" |), "number" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "number" |),
           Constant.int 1
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "check_gas_limit" |),
+        M.get_name (| globals, locals_stack, "check_gas_limit" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "gas_limit" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "gas_limit" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
           ],
           make_dict []
         |),
         Constant.int 32
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_difficulty" ,
       M.call (|
-        M.get_name (| globals, "calculate_block_difficulty" |),
+        M.get_name (| globals, locals_stack, "calculate_block_difficulty" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |);
-          M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "timestamp" |);
-          M.get_field (| M.get_name (| globals, "parent_header" |), "difficulty" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "timestamp" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "parent_header" |), "difficulty" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |),
-        M.get_name (| globals, "block_difficulty" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |),
+        M.get_name (| globals, locals_stack, "block_difficulty" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_parent_hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "parent_header" |)
+              M.get_name (| globals, locals_stack, "parent_header" |)
             ],
             make_dict []
           |)
@@ -600,28 +606,29 @@ Definition validate_header : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |),
-        M.get_name (| globals, "block_parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "block_parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "validate_proof_of_work" |),
+    M.get_name (| globals, locals_stack, "validate_proof_of_work" |),
     make_list [
-      M.get_name (| globals, "header" |)
+      M.get_name (| globals, locals_stack, "header" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Generate rlp hash of the header which is to be used for Proof-of-Work
     verification.
@@ -647,26 +654,26 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_data_without_pow_artefacts" ,
       make_list [
-        M.get_field (| M.get_name (| globals, "header" |), "parent_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "ommers_hash" |);
-        M.get_field (| M.get_name (| globals, "header" |), "coinbase" |);
-        M.get_field (| M.get_name (| globals, "header" |), "state_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "transactions_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "receipt_root" |);
-        M.get_field (| M.get_name (| globals, "header" |), "bloom" |);
-        M.get_field (| M.get_name (| globals, "header" |), "difficulty" |);
-        M.get_field (| M.get_name (| globals, "header" |), "number" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_limit" |);
-        M.get_field (| M.get_name (| globals, "header" |), "gas_used" |);
-        M.get_field (| M.get_name (| globals, "header" |), "timestamp" |);
-        M.get_field (| M.get_name (| globals, "header" |), "extra_data" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "parent_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "ommers_hash" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "coinbase" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "state_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "transactions_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "receipt_root" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "bloom" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_limit" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "gas_used" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "timestamp" |);
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "extra_data" |)
       ]
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "header_data_without_pow_artefacts" |)
+          M.get_name (| globals, locals_stack, "header_data_without_pow_artefacts" |)
         ],
         make_dict []
       |)
@@ -674,8 +681,9 @@ Definition generate_header_hash_for_pow : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_proof_of_work : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the Proof of Work constraints.
 
@@ -693,9 +701,9 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "header_hash" ,
       M.call (|
-        M.get_name (| globals, "generate_header_hash_for_pow" |),
+        M.get_name (| globals, locals_stack, "generate_header_hash_for_pow" |),
         make_list [
-          M.get_name (| globals, "header" |)
+          M.get_name (| globals, locals_stack, "header" |)
         ],
         make_dict []
       |)
@@ -703,25 +711,25 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "cache" ,
       M.call (|
-        M.get_name (| globals, "generate_cache" |),
+        M.get_name (| globals, locals_stack, "generate_cache" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "header" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "mix_digest" |); M.get_name (| globals, "result" |) ],
+      make_tuple [ M.get_name (| globals, locals_stack, "mix_digest" |); M.get_name (| globals, locals_stack, "result" |) ],
       M.call (|
-        M.get_name (| globals, "hashimoto_light" |),
+        M.get_name (| globals, locals_stack, "hashimoto_light" |),
         make_list [
-          M.get_name (| globals, "header_hash" |);
-          M.get_field (| M.get_name (| globals, "header" |), "nonce" |);
-          M.get_name (| globals, "cache" |);
+          M.get_name (| globals, locals_stack, "header_hash" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "nonce" |);
+          M.get_name (| globals, locals_stack, "cache" |);
           M.call (|
-            M.get_name (| globals, "dataset_size" |),
+            M.get_name (| globals, locals_stack, "dataset_size" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "header" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "header" |), "number" |)
             ],
             make_dict []
           |)
@@ -730,41 +738,42 @@ Definition validate_proof_of_work : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_name (| globals, "mix_digest" |),
-        M.get_field (| M.get_name (| globals, "header" |), "mix_digest" |)
+        M.get_name (| globals, locals_stack, "mix_digest" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "header" |), "mix_digest" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "Uint" |), "from_be_bytes" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_be_bytes" |),
           make_list [
-            M.get_name (| globals, "result" |)
+            M.get_name (| globals, locals_stack, "result" |)
           ],
           make_dict []
         |),
         BinOp.floor_div (|
-          M.get_name (| globals, "U256_CEIL_VALUE" |),
-          M.get_field (| M.get_name (| globals, "header" |), "difficulty" |)
+          M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "header" |), "difficulty" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition check_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "gas_available" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "gas_available" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if the transaction is includable in the block.
 
@@ -786,34 +795,35 @@ Definition check_transaction : Value.t -> Value.t -> M :=
         If the transaction is not includable.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_address" ,
       M.call (|
-        M.get_name (| globals, "recover_sender" |),
+        M.get_name (| globals, locals_stack, "recover_sender" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "sender_address" |)
+      M.get_name (| globals, locals_stack, "sender_address" |)
     |) in
     M.pure Constant.None_)).
 
 Definition make_receipt : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx"; "post_state"; "cumulative_gas_used"; "logs" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Make the receipt for a transaction that was executed.
 
@@ -837,13 +847,13 @@ Definition make_receipt : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "receipt" ,
       M.call (|
-        M.get_name (| globals, "Receipt" |),
+        M.get_name (| globals, locals_stack, "Receipt" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     |) in
     M.pure Constant.None_)).
 
@@ -858,8 +868,9 @@ Definition ApplyBodyOutput : Value.t :=
     ].
 
 Definition apply_body : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_hashes"; "coinbase"; "block_number"; "block_gas_limit"; "block_time"; "block_difficulty"; "transactions"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a block.
 
@@ -900,50 +911,50 @@ Definition apply_body : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "gas_available" ,
-      M.get_name (| globals, "block_gas_limit" |)
+      M.get_name (| globals, locals_stack, "block_gas_limit" |)
     |) in
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "i" |); M.get_name (| globals, "tx" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "i" |); M.get_name (| globals, locals_stack, "tx" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "transactions" |)
+        M.get_name (| globals, locals_stack, "transactions" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "transactions_trie" |);
+      M.get_name (| globals, locals_stack, "transactions_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "tx" |)
+      M.get_name (| globals, locals_stack, "tx" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "sender_address" ,
             M.call (|
-              M.get_name (| globals, "check_transaction" |),
+              M.get_name (| globals, locals_stack, "check_transaction" |),
               make_list [
-                M.get_name (| globals, "tx" |);
-                M.get_name (| globals, "gas_available" |)
+                M.get_name (| globals, locals_stack, "tx" |);
+                M.get_name (| globals, locals_stack, "gas_available" |)
               ],
               make_dict []
             |)
@@ -951,18 +962,18 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "env" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "vm" |), "Environment" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "vm" |), "Environment" |),
               make_list [],
               make_dict []
             |)
           |) in
           let _ := M.assign (|
-            make_tuple [ M.get_name (| globals, "gas_used" |); M.get_name (| globals, "logs" |) ],
+            make_tuple [ M.get_name (| globals, locals_stack, "gas_used" |); M.get_name (| globals, locals_stack, "logs" |) ],
             M.call (|
-              M.get_name (| globals, "process_transaction" |),
+              M.get_name (| globals, locals_stack, "process_transaction" |),
               make_list [
-                M.get_name (| globals, "env" |);
-                M.get_name (| globals, "tx" |)
+                M.get_name (| globals, locals_stack, "env" |);
+                M.get_name (| globals, locals_stack, "tx" |)
               ],
               make_dict []
             |)
@@ -970,55 +981,55 @@ Definition apply_body : Value.t -> Value.t -> M :=
           let _ := M.assign_op_local (|
             BinOp.sub,
             "gas_available",
-            M.get_name (| globals, "gas_used" |)
+            M.get_name (| globals, locals_stack, "gas_used" |)
           |) in
           let _ := M.assign_local (|
             "receipt" ,
             M.call (|
-              M.get_name (| globals, "make_receipt" |),
+              M.get_name (| globals, locals_stack, "make_receipt" |),
               make_list [
-                M.get_name (| globals, "tx" |);
+                M.get_name (| globals, locals_stack, "tx" |);
                 M.call (|
-                  M.get_name (| globals, "state_root" |),
+                  M.get_name (| globals, locals_stack, "state_root" |),
                   make_list [
-                    M.get_name (| globals, "state" |)
+                    M.get_name (| globals, locals_stack, "state" |)
                   ],
                   make_dict []
                 |);
                 BinOp.sub (|
-                  M.get_name (| globals, "block_gas_limit" |),
-                  M.get_name (| globals, "gas_available" |)
+                  M.get_name (| globals, locals_stack, "block_gas_limit" |),
+                  M.get_name (| globals, locals_stack, "gas_available" |)
                 |);
-                M.get_name (| globals, "logs" |)
+                M.get_name (| globals, locals_stack, "logs" |)
               ],
               make_dict []
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "receipts_trie" |);
+      M.get_name (| globals, locals_stack, "receipts_trie" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "i" |)
+              M.get_name (| globals, locals_stack, "i" |)
             ],
             make_dict []
           |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "receipt" |)
+      M.get_name (| globals, locals_stack, "receipt" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_op_local (|
             BinOp.add,
             "block_logs",
-            M.get_name (| globals, "logs" |)
+            M.get_name (| globals, locals_stack, "logs" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1027,56 +1038,56 @@ Definition apply_body : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "pay_rewards" |),
+    M.get_name (| globals, locals_stack, "pay_rewards" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "block_number" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "ommers" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "block_number" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommers" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "block_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "block_gas_limit" |),
-        M.get_name (| globals, "gas_available" |)
+        M.get_name (| globals, locals_stack, "block_gas_limit" |),
+        M.get_name (| globals, locals_stack, "gas_available" |)
       |)
     |) in
     let _ := M.assign_local (|
       "block_logs_bloom" ,
       M.call (|
-        M.get_name (| globals, "logs_bloom" |),
+        M.get_name (| globals, locals_stack, "logs_bloom" |),
         make_list [
-          M.get_name (| globals, "block_logs" |)
+          M.get_name (| globals, locals_stack, "block_logs" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ApplyBodyOutput" |),
+        M.get_name (| globals, locals_stack, "ApplyBodyOutput" |),
         make_list [
-          M.get_name (| globals, "block_gas_used" |);
+          M.get_name (| globals, locals_stack, "block_gas_used" |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "transactions_trie" |)
+              M.get_name (| globals, locals_stack, "transactions_trie" |)
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
-              M.get_name (| globals, "receipts_trie" |)
+              M.get_name (| globals, locals_stack, "receipts_trie" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "block_logs_bloom" |);
+          M.get_name (| globals, locals_stack, "block_logs_bloom" |);
           M.call (|
-            M.get_name (| globals, "state_root" |),
+            M.get_name (| globals, locals_stack, "state_root" |),
             make_list [
-              M.get_name (| globals, "state" |)
+              M.get_name (| globals, locals_stack, "state" |)
             ],
             make_dict []
           |)
@@ -1087,8 +1098,9 @@ Definition apply_body : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition validate_ommers : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "ommers"; "block_header"; "chain" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "ommers"; "block_header"; "chain" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the ommers mentioned in the block.
 
@@ -1113,27 +1125,27 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_hash" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
         make_list [
-          M.get_name (| globals, "block_header" |)
+          M.get_name (| globals, locals_stack, "block_header" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_field (| M.get_name (| globals, "rlp" |), "rlp_hash" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "rlp_hash" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "ommers_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "ommers_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1142,9 +1154,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
@@ -1162,46 +1174,46 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "ommer" |), "number" |),
-            M.get_field (| M.get_name (| globals, "block_header" |), "number" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_parent_header" ,
             M.get_field (| M.get_subscript (|
-              M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
               BinOp.sub (|
                 UnOp.sub (| BinOp.sub (|
-                  M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |) |),
                 Constant.int 1
               |)
             |), "header" |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "validate_header" |),
+    M.get_name (| globals, locals_stack, "validate_header" |),
     make_list [
-      M.get_name (| globals, "ommer" |);
-      M.get_name (| globals, "ommer_parent_header" |)
+      M.get_name (| globals, locals_stack, "ommer" |);
+      M.get_name (| globals, locals_stack, "ommer_parent_header" |)
     ],
     make_dict []
   |) in
@@ -1212,19 +1224,19 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt_e (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers" |)
+            M.get_name (| globals, locals_stack, "ommers" |)
           ],
           make_dict []
         |),
         Constant.int 2
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1233,23 +1245,23 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
       Constant.str "(* At expr: unsupported node type: ListComp *)"
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "ommers_hashes" |)
+            M.get_name (| globals, locals_stack, "ommers_hashes" |)
           ],
           make_dict []
         |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "set" |),
+              M.get_name (| globals, locals_stack, "set" |),
               make_list [
-                M.get_name (| globals, "ommers_hashes" |)
+                M.get_name (| globals, locals_stack, "ommers_hashes" |)
               ],
               make_dict []
             |)
@@ -1257,16 +1269,16 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "recent_canonical_blocks" ,
       M.slice (|
-        M.get_field (| M.get_name (| globals, "chain" |), "blocks" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "chain" |), "blocks" |),
         UnOp.sub (| BinOp.add (|
-          M.get_name (| globals, "MAX_OMMER_DEPTH" |),
+          M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |),
           Constant.int 1
         |) |),
         Constant.None_,
@@ -1280,13 +1292,13 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "block" |),
-        M.get_name (| globals, "recent_canonical_blocks" |),
+        M.get_name (| globals, locals_stack, "block" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_blocks" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "recent_ommers_hashes" ,
             M.call (|
-              M.get_field (| M.get_name (| globals, "recent_ommers_hashes" |), "union" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "recent_ommers_hashes" |), "union" |),
               make_list [
                 Constant.str "(* At expr: unsupported node type: SetComp *)"
               ],
@@ -1301,11 +1313,11 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "ommer_index" |); M.get_name (| globals, "ommer" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "ommer_index" |); M.get_name (| globals, locals_stack, "ommer" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "ommers" |)
+        M.get_name (| globals, locals_stack, "ommers" |)
       ],
       make_dict []
     |),
@@ -1313,88 +1325,88 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "ommer_hash" ,
             M.get_subscript (|
-              M.get_name (| globals, "ommers_hashes" |),
-              M.get_name (| globals, "ommer_index" |)
+              M.get_name (| globals, locals_stack, "ommers_hashes" |),
+              M.get_name (| globals, locals_stack, "ommer_index" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "block_hash" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "block_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_in (|
-        M.get_name (| globals, "ommer_hash" |),
-        M.get_name (| globals, "recent_ommers_hashes" |)
+        M.get_name (| globals, locals_stack, "ommer_hash" |),
+        M.get_name (| globals, locals_stack, "recent_ommers_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "ommer_age" ,
             BinOp.sub (|
-              M.get_field (| M.get_name (| globals, "block_header" |), "number" |),
-              M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "number" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt_e (|
           Constant.int 1,
-          M.get_name (| globals, "ommer_age" |)
+          M.get_name (| globals, locals_stack, "ommer_age" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "ommer_age" |),
-            M.get_name (| globals, "MAX_OMMER_DEPTH" |)
+            M.get_name (| globals, locals_stack, "ommer_age" |),
+            M.get_name (| globals, locals_stack, "MAX_OMMER_DEPTH" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.in_ (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_name (| globals, "recent_canonical_block_hashes" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_name (| globals, locals_stack, "recent_canonical_block_hashes" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_field (| M.get_name (| globals, "ommer" |), "parent_hash" |),
-        M.get_field (| M.get_name (| globals, "block_header" |), "parent_hash" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "parent_hash" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "block_header" |), "parent_hash" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
@@ -1407,8 +1419,9 @@ Definition validate_ommers : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pay_rewards : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "block_number"; "coinbase"; "ommers" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "block_number"; "coinbase"; "ommers" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pay rewards to the block miner as well as the ommers miners.
 
@@ -1437,44 +1450,44 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "miner_reward" ,
       BinOp.add (|
-        M.get_name (| globals, "BLOCK_REWARD" |),
+        M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
         BinOp.mult (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "ommers" |)
+              M.get_name (| globals, locals_stack, "ommers" |)
             ],
             make_dict []
           |),
           BinOp.floor_div (|
-            M.get_name (| globals, "BLOCK_REWARD" |),
+            M.get_name (| globals, locals_stack, "BLOCK_REWARD" |),
             Constant.int 32
           |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "coinbase" |);
-      M.get_name (| globals, "miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "coinbase" |);
+      M.get_name (| globals, locals_stack, "miner_reward" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "ommer" |),
-        M.get_name (| globals, "ommers" |),
+        M.get_name (| globals, locals_stack, "ommer" |),
+        M.get_name (| globals, locals_stack, "ommers" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "ommer_age" ,
             M.call (|
-              M.get_name (| globals, "U256" |),
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 BinOp.sub (|
-                  M.get_name (| globals, "block_number" |),
-                  M.get_field (| M.get_name (| globals, "ommer" |), "number" |)
+                  M.get_name (| globals, locals_stack, "block_number" |),
+                  M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "number" |)
                 |)
               ],
               make_dict []
@@ -1486,19 +1499,19 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
               BinOp.mult (|
                 BinOp.sub (|
                   Constant.int 8,
-                  M.get_name (| globals, "ommer_age" |)
+                  M.get_name (| globals, locals_stack, "ommer_age" |)
                 |),
-                M.get_name (| globals, "BLOCK_REWARD" |)
+                M.get_name (| globals, locals_stack, "BLOCK_REWARD" |)
               |),
               Constant.int 8
             |)
           |) in
           let _ := M.call (|
-    M.get_name (| globals, "create_ether" |),
+    M.get_name (| globals, locals_stack, "create_ether" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_field (| M.get_name (| globals, "ommer" |), "coinbase" |);
-      M.get_name (| globals, "ommer_miner_reward" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "ommer" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "ommer_miner_reward" |)
     ],
     make_dict []
   |) in
@@ -1511,8 +1524,9 @@ Definition pay_rewards : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "env"; "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "env"; "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -1540,30 +1554,30 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         Logs generated during execution.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "validate_transaction" |),
+        M.get_name (| globals, locals_stack, "validate_transaction" |),
         make_list [
-          M.get_name (| globals, "tx" |)
+          M.get_name (| globals, locals_stack, "tx" |)
         ],
         make_dict []
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender" ,
-      M.get_field (| M.get_name (| globals, "env" |), "origin" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "origin" |)
     |) in
     let _ := M.assign_local (|
       "sender_account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "env" |), "state" |);
-          M.get_name (| globals, "sender" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender" |)
         ],
         make_dict []
       |)
@@ -1571,98 +1585,98 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_fee" ,
       BinOp.mult (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "nonce" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "nonce" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "nonce" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.gt_e (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
         BinOp.add (|
-          M.get_name (| globals, "gas_fee" |),
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |)
+          M.get_name (| globals, locals_stack, "gas_fee" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |)
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.eq (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "code" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "code" |),
         M.call (|
-          M.get_name (| globals, "bytearray" |),
+          M.get_name (| globals, locals_stack, "bytearray" |),
           make_list [],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "gas" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
         M.call (|
-          M.get_name (| globals, "calculate_intrinsic_cost" |),
+          M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
           make_list [
-            M.get_name (| globals, "tx" |)
+            M.get_name (| globals, locals_stack, "tx" |)
           ],
           make_dict []
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "sender_balance_after_gas_fee" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "sender_account" |), "balance" |),
-        M.get_name (| globals, "gas_fee" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "sender_account" |), "balance" |),
+        M.get_name (| globals, locals_stack, "gas_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_gas_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_gas_fee" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message" ,
       M.call (|
-        M.get_name (| globals, "prepare_message" |),
+        M.get_name (| globals, locals_stack, "prepare_message" |),
         make_list [
-          M.get_name (| globals, "sender" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "value" |);
-          M.get_field (| M.get_name (| globals, "tx" |), "data" |);
-          M.get_name (| globals, "gas" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "sender" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |);
+          M.get_name (| globals, locals_stack, "gas" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1670,10 +1684,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "output" ,
       M.call (|
-        M.get_name (| globals, "process_message_call" |),
+        M.get_name (| globals, locals_stack, "process_message_call" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -1681,20 +1695,20 @@ Definition process_transaction : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas_used" ,
       BinOp.sub (|
-        M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-        M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
       |)
     |) in
     let _ := M.assign_local (|
       "gas_refund" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
           BinOp.floor_div (|
-            M.get_name (| globals, "gas_used" |),
+            M.get_name (| globals, locals_stack, "gas_used" |),
             Constant.int 2
           |);
-          M.get_field (| M.get_name (| globals, "output" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "refund_counter" |)
         ],
         make_dict []
       |)
@@ -1703,10 +1717,10 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "gas_refund_amount" ,
       BinOp.mult (|
         BinOp.add (|
-          M.get_field (| M.get_name (| globals, "output" |), "gas_left" |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -1714,41 +1728,41 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.sub (|
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "tx" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "output" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "output" |), "gas_left" |)
           |),
-          M.get_name (| globals, "gas_refund" |)
+          M.get_name (| globals, locals_stack, "gas_refund" |)
         |),
-        M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |)
       |)
     |) in
     let _ := M.assign_local (|
       "total_gas_used" ,
       BinOp.sub (|
-        M.get_name (| globals, "gas_used" |),
-        M.get_name (| globals, "gas_refund" |)
+        M.get_name (| globals, locals_stack, "gas_used" |),
+        M.get_name (| globals, locals_stack, "gas_refund" |)
       |)
     |) in
     let _ := M.assign_local (|
       "sender_balance_after_refund" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_name (| globals, "sender" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "sender" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "gas_refund_amount" |)
+        M.get_name (| globals, locals_stack, "gas_refund_amount" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "sender" |);
-      M.get_name (| globals, "sender_balance_after_refund" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "sender" |);
+      M.get_name (| globals, locals_stack, "sender_balance_after_refund" |)
     ],
     make_dict []
   |) in
@@ -1756,35 +1770,35 @@ Definition process_transaction : Value.t -> Value.t -> M :=
       "coinbase_balance_after_mining_fee" ,
       BinOp.add (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "get_account" |),
+          M.get_name (| globals, locals_stack, "get_account" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "env" |), "state" |);
-            M.get_field (| M.get_name (| globals, "env" |), "coinbase" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+            M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |)
           ],
           make_dict []
         |), "balance" |),
-        M.get_name (| globals, "transaction_fee" |)
+        M.get_name (| globals, locals_stack, "transaction_fee" |)
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "env" |), "coinbase" |);
-      M.get_name (| globals, "coinbase_balance_after_mining_fee" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "coinbase" |);
+      M.get_name (| globals, locals_stack, "coinbase_balance_after_mining_fee" |)
     ],
     make_dict []
   |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "address" |),
-        M.get_field (| M.get_name (| globals, "output" |), "accounts_to_delete" |),
+        M.get_name (| globals, locals_stack, "address" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "output" |), "accounts_to_delete" |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_name (| globals, "destroy_account" |),
+    M.get_name (| globals, locals_stack, "destroy_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
@@ -1795,13 +1809,14 @@ Definition process_transaction : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      make_tuple [ M.get_name (| globals, "total_gas_used" |); M.get_field (| M.get_name (| globals, "output" |), "logs" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "total_gas_used" |); M.get_field (| M.get_name (| globals, locals_stack, "output" |), "logs" |) ]
     |) in
     M.pure Constant.None_)).
 
 Definition validate_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Verifies a transaction.
 
@@ -1830,17 +1845,17 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
       BoolOp.and (|
         Compare.lt_e (|
           M.call (|
-            M.get_name (| globals, "calculate_intrinsic_cost" |),
+            M.get_name (| globals, locals_stack, "calculate_intrinsic_cost" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |),
-          M.get_field (| M.get_name (| globals, "tx" |), "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "tx" |), "nonce" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |),
             BinOp.sub (|
               BinOp.pow (|
                 Constant.int 2,
@@ -1855,8 +1870,9 @@ Definition validate_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas that is charged before execution is started.
 
@@ -1885,14 +1901,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "byte" |),
-        M.get_field (| M.get_name (| globals, "tx" |), "data" |),
+        M.get_name (| globals, locals_stack, "byte" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1900,7 +1916,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_ZERO" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -1908,7 +1924,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
               let _ := M.assign_op_local (|
                 BinOp.add,
                 "data_cost",
-                M.get_name (| globals, "TX_DATA_COST_PER_NON_ZERO" |)
+                M.get_name (| globals, locals_stack, "TX_DATA_COST_PER_NON_ZERO" |)
               |) in
               M.pure Constant.None_
             )) |) in
@@ -1922,9 +1938,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "tx" |), "to" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -1935,7 +1951,7 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "create_cost" ,
-          M.get_name (| globals, "TX_CREATE_COST" |)
+          M.get_name (| globals, locals_stack, "TX_CREATE_COST" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1948,14 +1964,14 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "TX_BASE_COST" |),
-              M.get_name (| globals, "data_cost" |)
+              M.get_name (| globals, locals_stack, "TX_BASE_COST" |),
+              M.get_name (| globals, locals_stack, "data_cost" |)
             |),
-            M.get_name (| globals, "create_cost" |)
+            M.get_name (| globals, locals_stack, "create_cost" |)
           |)
         ],
         make_dict []
@@ -1964,8 +1980,9 @@ Definition calculate_intrinsic_cost : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition recover_sender : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Extracts the sender address from a transaction.
 
@@ -1986,84 +2003,84 @@ Definition recover_sender : Value.t -> Value.t -> M :=
         The address of the account that signed the transaction.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_name (| globals, "v" |); M.get_name (| globals, "r" |); M.get_name (| globals, "s" |) ],
-      make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "v" |); M.get_field (| M.get_name (| globals, "tx" |), "r" |); M.get_field (| M.get_name (| globals, "tx" |), "s" |) ]
+      make_tuple [ M.get_name (| globals, locals_stack, "v" |); M.get_name (| globals, locals_stack, "r" |); M.get_name (| globals, locals_stack, "s" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "v" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "r" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "s" |) ]
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.or (|
         Compare.eq (|
-          M.get_name (| globals, "v" |),
+          M.get_name (| globals, locals_stack, "v" |),
           Constant.int 27
         |),
         ltac:(M.monadic (
           Compare.eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 28
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "r" |)
+          M.get_name (| globals, locals_stack, "r" |)
         |),
         ltac:(M.monadic (
           Compare.lt (|
-            M.get_name (| globals, "r" |),
-            M.get_name (| globals, "SECP256K1N" |)
+            M.get_name (| globals, locals_stack, "r" |),
+            M.get_name (| globals, locals_stack, "SECP256K1N" |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       BoolOp.and (|
         Compare.lt (|
           Constant.int 0,
-          M.get_name (| globals, "s" |)
+          M.get_name (| globals, locals_stack, "s" |)
         |),
         ltac:(M.monadic (
           Compare.lt_e (|
-            M.get_name (| globals, "s" |),
+            M.get_name (| globals, locals_stack, "s" |),
             BinOp.floor_div (|
-              M.get_name (| globals, "SECP256K1N" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |),
               Constant.int 2
             |)
           |)
         ))
       |);
-      M.get_name (| globals, "InvalidBlock" |)
+      M.get_name (| globals, locals_stack, "InvalidBlock" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "public_key" ,
       M.call (|
-        M.get_name (| globals, "secp256k1_recover" |),
+        M.get_name (| globals, locals_stack, "secp256k1_recover" |),
         make_list [
-          M.get_name (| globals, "r" |);
-          M.get_name (| globals, "s" |);
+          M.get_name (| globals, locals_stack, "r" |);
+          M.get_name (| globals, locals_stack, "s" |);
           BinOp.sub (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |);
           M.call (|
-            M.get_name (| globals, "signing_hash" |),
+            M.get_name (| globals, locals_stack, "signing_hash" |),
             make_list [
-              M.get_name (| globals, "tx" |)
+              M.get_name (| globals, locals_stack, "tx" |)
             ],
             make_dict []
           |)
@@ -2073,13 +2090,13 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_name (| globals, "keccak256" |),
+              M.get_name (| globals, locals_stack, "keccak256" |),
               make_list [
-                M.get_name (| globals, "public_key" |)
+                M.get_name (| globals, locals_stack, "public_key" |)
               ],
               make_dict []
             |),
@@ -2094,8 +2111,9 @@ Definition recover_sender : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition signing_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "tx" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "tx" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compute the hash of a transaction used in the signature.
 
@@ -2115,12 +2133,12 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              make_tuple [ M.get_field (| M.get_name (| globals, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, "tx" |), "to" |); M.get_field (| M.get_name (| globals, "tx" |), "value" |); M.get_field (| M.get_name (| globals, "tx" |), "data" |) ]
+              make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas_price" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "gas" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "to" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "value" |); M.get_field (| M.get_name (| globals, locals_stack, "tx" |), "data" |) ]
             ],
             make_dict []
           |)
@@ -2131,8 +2149,9 @@ Definition signing_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_header_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "header" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "header" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the hash of a block header.
 
@@ -2166,12 +2185,12 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
-              M.get_name (| globals, "header" |)
+              M.get_name (| globals, locals_stack, "header" |)
             ],
             make_dict []
           |)
@@ -2182,8 +2201,9 @@ Definition compute_header_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition check_gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas_limit"; "parent_gas_limit" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas_limit"; "parent_gas_limit" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Validates the gas limit for a block.
 
@@ -2214,18 +2234,18 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "max_adjustment_delta" ,
       BinOp.floor_div (|
-        M.get_name (| globals, "parent_gas_limit" |),
-        M.get_name (| globals, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
+        M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+        M.get_name (| globals, locals_stack, "GAS_LIMIT_ADJUSTMENT_FACTOR" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.add (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2242,10 +2262,10 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "gas_limit" |),
           BinOp.sub (|
-            M.get_name (| globals, "parent_gas_limit" |),
-            M.get_name (| globals, "max_adjustment_delta" |)
+            M.get_name (| globals, locals_stack, "parent_gas_limit" |),
+            M.get_name (| globals, locals_stack, "max_adjustment_delta" |)
           |)
         |),
       (* then *)
@@ -2262,8 +2282,8 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_limit" |),
-          M.get_name (| globals, "GAS_LIMIT_MINIMUM" |)
+          M.get_name (| globals, locals_stack, "gas_limit" |),
+          M.get_name (| globals, locals_stack, "GAS_LIMIT_MINIMUM" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -2281,8 +2301,9 @@ Definition check_gas_limit : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "block_number"; "block_timestamp"; "parent_timestamp"; "parent_difficulty" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes difficulty of a block using its header and parent header.
 
@@ -2324,26 +2345,26 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.mult (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "parent_difficulty" |)
+              M.get_name (| globals, locals_stack, "parent_difficulty" |)
             ],
             make_dict []
           |),
           Constant.int 2048
         |),
         M.call (|
-          M.get_name (| globals, "max" |),
+          M.get_name (| globals, locals_stack, "max" |),
           make_list [
             BinOp.sub (|
               Constant.int 1,
               BinOp.floor_div (|
                 M.call (|
-                  M.get_name (| globals, "int" |),
+                  M.get_name (| globals, locals_stack, "int" |),
                   make_list [
                     BinOp.sub (|
-                      M.get_name (| globals, "block_timestamp" |),
-                      M.get_name (| globals, "parent_timestamp" |)
+                      M.get_name (| globals, locals_stack, "block_timestamp" |),
+                      M.get_name (| globals, locals_stack, "parent_timestamp" |)
                     |)
                   ],
                   make_dict []
@@ -2361,13 +2382,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       "difficulty" ,
       BinOp.add (|
         M.call (|
-          M.get_name (| globals, "int" |),
+          M.get_name (| globals, locals_stack, "int" |),
           make_list [
-            M.get_name (| globals, "parent_difficulty" |)
+            M.get_name (| globals, locals_stack, "parent_difficulty" |)
           ],
           make_dict []
         |),
-        M.get_name (| globals, "offset" |)
+        M.get_name (| globals, locals_stack, "offset" |)
       |)
     |) in
     let _ := M.assign_local (|
@@ -2375,9 +2396,9 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       BinOp.sub (|
         BinOp.floor_div (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
-              M.get_name (| globals, "block_number" |)
+              M.get_name (| globals, locals_stack, "block_number" |)
             ],
             make_dict []
           |),
@@ -2390,7 +2411,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "num_bomb_periods" |),
+          M.get_name (| globals, locals_stack, "num_bomb_periods" |),
           Constant.int 0
         |),
       (* then *)
@@ -2400,7 +2421,7 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
           "difficulty",
           BinOp.pow (|
     Constant.int 2,
-    M.get_name (| globals, "num_bomb_periods" |)
+    M.get_name (| globals, locals_stack, "num_bomb_periods" |)
   |)
         |) in
         M.pure Constant.None_
@@ -2410,13 +2431,13 @@ Definition calculate_block_difficulty : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "max" |),
+            M.get_name (| globals, locals_stack, "max" |),
             make_list [
-              M.get_name (| globals, "difficulty" |);
-              M.get_name (| globals, "MINIMUM_DIFFICULTY" |)
+              M.get_name (| globals, locals_stack, "difficulty" |);
+              M.get_name (| globals, locals_stack, "MINIMUM_DIFFICULTY" |)
             ],
             make_dict []
           |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/fork_types.v b/CoqOfPython/ethereum/tangerine_whistle/fork_types.v
index d749dca..76d92b0 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/fork_types.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/fork_types.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.fork_types".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.fork_types".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,15 +44,15 @@ Axiom ethereum_crypto_hash_imports_keccak256 :
   IsImported globals "ethereum.crypto.hash" "keccak256".
 
 Definition Address : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes20" |)
+  M.get_name (| globals, locals_stack, "Bytes20" |)
 )).
 
 Definition Root : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Hash32" |)
+  M.get_name (| globals, locals_stack, "Hash32" |)
 )).
 
 Definition Bloom : Value.t := M.run ltac:(M.monadic (
-  M.get_name (| globals, "Bytes256" |)
+  M.get_name (| globals, locals_stack, "Bytes256" |)
 )).
 
 Definition Account : Value.t :=
@@ -65,15 +67,16 @@ Definition Account : Value.t :=
 
 Definition EMPTY_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Account" |),
+    M.get_name (| globals, locals_stack, "Account" |),
     make_list [],
     make_dict []
   |)
 )).
 
 Definition encode_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "raw_account_data"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "raw_account_data"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode `Account` dataclass.
 
@@ -82,12 +85,12 @@ Definition encode_account : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          make_tuple [ M.get_field (| M.get_name (| globals, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, "raw_account_data" |), "balance" |); M.get_name (| globals, "storage_root" |); M.call (|
-            M.get_name (| globals, "keccak256" |),
+          make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "nonce" |); M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "balance" |); M.get_name (| globals, locals_stack, "storage_root" |); M.call (|
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "raw_account_data" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "raw_account_data" |), "code" |)
             ],
             make_dict []
           |) ]
diff --git a/CoqOfPython/ethereum/tangerine_whistle/state.v b/CoqOfPython/ethereum/tangerine_whistle/state.v
index ffd4f3b..d94f612 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/state.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/state.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.state".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.state".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -83,20 +85,22 @@ Definition State : Value.t :=
     ].
 
 Definition close_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Free resources held by the state. Used by optimized implementations to
     release file descriptors.
     " in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) |) in
-    let _ := M.delete (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) |) in
+    let _ := M.delete (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) in
     M.pure Constant.None_)).
 
 Definition begin_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Start a state transaction.
 
@@ -109,12 +113,12 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "append" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "append" |),
     make_list [
       make_tuple [ M.call (|
-        M.get_name (| globals, "copy_trie" |),
+        M.get_name (| globals, locals_stack, "copy_trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |); Constant.str "(* At expr: unsupported node type: DictComp *)" ]
@@ -124,8 +128,9 @@ Definition begin_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition commit_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Commit a state transaction.
 
@@ -135,15 +140,16 @@ Definition commit_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
     make_list [],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition rollback_transaction : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Rollback a state transaction, resetting the state to the point when the
     corresponding `start_transaction()` call was made.
@@ -154,9 +160,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
         The state.
     " in
     let _ := M.assign (|
-      make_tuple [ M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |) ],
+      make_tuple [ M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |); M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |) ],
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |), "pop" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -164,8 +170,9 @@ Definition rollback_transaction : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there
     is no account at the address.
@@ -188,10 +195,10 @@ Definition get_account : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account_optional" |),
+        M.get_name (| globals, locals_stack, "get_account_optional" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -200,31 +207,32 @@ Definition get_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "account" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "account" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "account" |)
+          M.get_name (| globals, locals_stack, "account" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition get_account_optional : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get the `Account` object at an address. Returns `None` (rather than
     `EMPTY_ACCOUNT`) if there is no account at the address.
@@ -244,22 +252,23 @@ Definition get_account_optional : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "account" |)
+      M.get_name (| globals, locals_stack, "account" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "account" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "account" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set the `Account` object at an address. Setting to `None` deletes
     the account (but not its storage, see `destroy_account()`).
@@ -274,19 +283,20 @@ Definition set_account : Value.t -> Value.t -> M :=
         Account to set at address.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "account" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "account" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition destroy_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the account at `address` and all of its storage.
 
@@ -302,18 +312,18 @@ Definition destroy_account : Value.t -> Value.t -> M :=
         Address of account to destroy.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       Constant.None_
     ],
     make_dict []
@@ -321,8 +331,9 @@ Definition destroy_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition destroy_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Completely remove the storage at `address`.
 
@@ -337,14 +348,14 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -354,8 +365,9 @@ Definition destroy_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition get_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Get a value at a storage key on an account. Returns `U256(0)` if the
     storage key has not been set previously.
@@ -377,9 +389,9 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -388,14 +400,14 @@ Definition get_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -410,30 +422,31 @@ Definition get_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "trie_get" |),
+        M.get_name (| globals, locals_stack, "trie_get" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "key" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "value" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition set_storage : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Set a value at a storage key on an account. Setting to `U256(0)` deletes
     the key.
@@ -451,10 +464,10 @@ Definition set_storage : Value.t -> Value.t -> M :=
     " in
     let _ := M.assert (| Compare.is_not (|
     M.call (|
-      M.get_name (| globals, "trie_get" |),
+      M.get_name (| globals, locals_stack, "trie_get" |),
       make_list [
-        M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |);
-        M.get_name (| globals, "address" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |);
+        M.get_name (| globals, locals_stack, "address" |)
       ],
       make_dict []
     |),
@@ -463,9 +476,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "trie" ,
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |), "get" |),
         make_list [
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -474,7 +487,7 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "trie" |),
+          M.get_name (| globals, locals_stack, "trie" |),
           Constant.None_
         |),
       (* then *)
@@ -482,17 +495,17 @@ Definition set_storage : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "trie" ,
           M.call (|
-            M.get_name (| globals, "Trie" |),
+            M.get_name (| globals, locals_stack, "Trie" |),
             make_list [],
             make_dict []
           |)
         |) in
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-            M.get_name (| globals, "address" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+            M.get_name (| globals, locals_stack, "address" |)
           |),
-          M.get_name (| globals, "trie" |)
+          M.get_name (| globals, locals_stack, "trie" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -500,11 +513,11 @@ Definition set_storage : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "trie_set" |),
+    M.get_name (| globals, locals_stack, "trie_set" |),
     make_list [
-      M.get_name (| globals, "trie" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "trie" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
@@ -512,14 +525,14 @@ Definition set_storage : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
           Constant.str "(* At expr: unsupported node type: Dict *)"
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-    M.get_name (| globals, "address" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+    M.get_name (| globals, locals_stack, "address" |)
   |) |) in
         M.pure Constant.None_
       (* else *)
@@ -529,8 +542,9 @@ Definition set_storage : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition storage_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the storage root of an account.
 
@@ -546,23 +560,23 @@ Definition storage_root : Value.t -> Value.t -> M :=
     root : `Root`
         Storage root of the account.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.in_ (|
-          M.get_name (| globals, "address" |),
-          M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |)
+          M.get_name (| globals, locals_stack, "address" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "root" |),
+            M.get_name (| globals, locals_stack, "root" |),
             make_list [
               M.get_subscript (|
-                M.get_field (| M.get_name (| globals, "state" |), "_storage_tries" |),
-                M.get_name (| globals, "address" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_storage_tries" |),
+                M.get_name (| globals, locals_stack, "address" |)
               |)
             ],
             make_dict []
@@ -572,15 +586,16 @@ Definition storage_root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "EMPTY_TRIE_ROOT" |)
+          M.get_name (| globals, locals_stack, "EMPTY_TRIE_ROOT" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition state_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculate the state root.
 
@@ -594,13 +609,13 @@ Definition state_root : Value.t -> Value.t -> M :=
     root : `Root`
         The state root.
     " in
-    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, "state" |), "_snapshots" |) |) |) in
+    let _ := M.assert (| UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_snapshots" |) |) |) in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "root" |),
+        M.get_name (| globals, locals_stack, "root" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "state" |), "_main_trie" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "state" |), "_main_trie" |)
         ],
         make_dict []
       |)
@@ -608,8 +623,9 @@ Definition state_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_exists : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account exists in the state trie
 
@@ -628,10 +644,10 @@ Definition account_exists : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       Compare.is_not (|
         M.call (|
-          M.get_name (| globals, "get_account_optional" |),
+          M.get_name (| globals, locals_stack, "get_account_optional" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |),
@@ -641,8 +657,9 @@ Definition account_exists : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if an account has non zero nonce or non empty code
 
@@ -662,10 +679,10 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "account" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_name (| globals, "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_name (| globals, locals_stack, "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |)
@@ -673,9 +690,9 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     let _ := M.return_ (|
       BoolOp.or (|
         Compare.not_eq (|
-          M.get_field (| M.get_name (| globals, "account" |), "nonce" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "account" |), "nonce" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -684,7 +701,7 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
         |),
         ltac:(M.monadic (
           Compare.not_eq (|
-            M.get_field (| M.get_name (| globals, "account" |), "code" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "account" |), "code" |),
             Constant.bytes ""
           |)
         ))
@@ -693,28 +710,29 @@ Definition account_has_code_or_nonce : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition modify_state : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "f" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "f" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modify an `Account` in the `State`.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
       M.call (|
-        M.get_name (| globals, "modify" |),
+        M.get_name (| globals, locals_stack, "modify" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_name (| globals, "state" |);
-              M.get_name (| globals, "address" |)
+              M.get_name (| globals, locals_stack, "state" |);
+              M.get_name (| globals, locals_stack, "address" |)
             ],
             make_dict []
           |);
-          M.get_name (| globals, "f" |)
+          M.get_name (| globals, locals_stack, "f" |)
         ],
         make_dict []
       |)
@@ -724,36 +742,38 @@ Definition modify_state : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition move_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "sender_address"; "recipient_address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "sender_address"; "recipient_address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Move funds between accounts.
     " in
 (* At stmt: unsupported node type: FunctionDef *)
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "sender_address" |);
-      M.get_name (| globals, "reduce_sender_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "sender_address" |);
+      M.get_name (| globals, locals_stack, "reduce_sender_balance" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "recipient_address" |);
-      M.get_name (| globals, "increase_recipient_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "recipient_address" |);
+      M.get_name (| globals, locals_stack, "increase_recipient_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_account_balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets the balance of an account.
 
@@ -770,19 +790,20 @@ Definition set_account_balance : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "set_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "set_balance" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition touch_account : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Initializes an account to state.
 
@@ -798,21 +819,21 @@ Definition touch_account : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_name (| globals, "state" |);
-            M.get_name (| globals, "address" |)
+            M.get_name (| globals, locals_stack, "state" |);
+            M.get_name (| globals, locals_stack, "address" |)
           ],
           make_dict []
         |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "set_account" |),
+    M.get_name (| globals, locals_stack, "set_account" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "EMPTY_ACCOUNT" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "EMPTY_ACCOUNT" |)
     ],
     make_dict []
   |) in
@@ -824,8 +845,9 @@ Definition touch_account : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition increment_nonce : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Increments the nonce of an account.
 
@@ -839,19 +861,20 @@ Definition increment_nonce : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_nonce" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_nonce" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition set_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sets Account code.
 
@@ -868,19 +891,20 @@ Definition set_code : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "write_code" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "write_code" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition create_ether : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "state"; "address"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "state"; "address"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Add newly created ether to an account.
 
@@ -895,11 +919,11 @@ Definition create_ether : Value.t -> Value.t -> M :=
     " in
 (* At stmt: unsupported node type: FunctionDef *)
     let _ := M.call (|
-    M.get_name (| globals, "modify_state" |),
+    M.get_name (| globals, locals_stack, "modify_state" |),
     make_list [
-      M.get_name (| globals, "state" |);
-      M.get_name (| globals, "address" |);
-      M.get_name (| globals, "increase_balance" |)
+      M.get_name (| globals, locals_stack, "state" |);
+      M.get_name (| globals, locals_stack, "address" |);
+      M.get_name (| globals, locals_stack, "increase_balance" |)
     ],
     make_dict []
   |) in
diff --git a/CoqOfPython/ethereum/tangerine_whistle/transactions.v b/CoqOfPython/ethereum/tangerine_whistle/transactions.v
index cfb821b..20fa717 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/transactions.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/transactions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.transactions".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.transactions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/tangerine_whistle/trie.v b/CoqOfPython/ethereum/tangerine_whistle/trie.v
index 1390bd6..2e13011 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/trie.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/trie.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.trie".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.trie".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -89,10 +91,10 @@ Axiom ethereum_tangerine_whistle_transactions_imports_Transaction :
 
 Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Root" |),
+    M.get_name (| globals, locals_stack, "Root" |),
     make_list [
       M.call (|
-        M.get_name (| globals, "hex_to_bytes" |),
+        M.get_name (| globals, locals_stack, "hex_to_bytes" |),
         make_list [
           Constant.str "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
         ],
@@ -105,14 +107,14 @@ Definition EMPTY_TRIE_ROOT : Value.t := M.run ltac:(M.monadic (
 
 Definition Node : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Bytes" |); M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |); M.get_name (| globals, "U256" |); Constant.None_ ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Bytes" |); M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |); M.get_name (| globals, locals_stack, "U256" |); Constant.None_ ]
   |)
 )).
 
 Definition K : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "K"
     ],
@@ -122,28 +124,28 @@ Definition K : Value.t := M.run ltac:(M.monadic (
 
 Definition V : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "TypeVar" |),
+    M.get_name (| globals, locals_stack, "TypeVar" |),
     make_list [
       Constant.str "V";
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Account" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Account" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Bytes" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Bytes" |)
       |);
-      M.get_name (| globals, "Bytes" |);
+      M.get_name (| globals, locals_stack, "Bytes" |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Transaction" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Transaction" |)
       |);
       M.get_subscript (|
-        M.get_name (| globals, "Optional" |),
-        M.get_name (| globals, "Receipt" |)
+        M.get_name (| globals, locals_stack, "Optional" |),
+        M.get_name (| globals, locals_stack, "Receipt" |)
       |);
-      M.get_name (| globals, "Uint" |);
-      M.get_name (| globals, "U256" |)
+      M.get_name (| globals, locals_stack, "Uint" |);
+      M.get_name (| globals, locals_stack, "U256" |)
     ],
     make_dict []
   |)
@@ -181,14 +183,15 @@ Definition BranchNode : Value.t :=
 
 Definition InternalNode : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "LeafNode" |); M.get_name (| globals, "ExtensionNode" |); M.get_name (| globals, "BranchNode" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "LeafNode" |); M.get_name (| globals, locals_stack, "ExtensionNode" |); M.get_name (| globals, locals_stack, "BranchNode" |) ]
   |)
 )).
 
 Definition encode_internal_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encodes a Merkle Trie node into its RLP form. The RLP will then be
     serialized into a `Bytes` and hashed unless it is less that 32 bytes
@@ -212,7 +215,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.is (|
-          M.get_name (| globals, "node" |),
+          M.get_name (| globals, locals_stack, "node" |),
           Constant.None_
         |),
       (* then *)
@@ -228,10 +231,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                M.get_name (| globals, "LeafNode" |)
+                M.get_name (| globals, locals_stack, "node" |);
+                M.get_name (| globals, locals_stack, "LeafNode" |)
               ],
               make_dict []
             |),
@@ -240,13 +243,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "unencoded" ,
               make_tuple [ M.call (|
-                M.get_name (| globals, "nibble_list_to_compact" |),
+                M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "node" |), "rest_of_key" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "node" |), "rest_of_key" |);
                   Constant.bool true
                 ],
                 make_dict []
-              |); M.get_field (| M.get_name (| globals, "node" |), "value" |) ]
+              |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |) ]
             |) in
             M.pure Constant.None_
           (* else *)
@@ -255,10 +258,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "ExtensionNode" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "ExtensionNode" |)
                   ],
                   make_dict []
                 |),
@@ -267,13 +270,13 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                 let _ := M.assign_local (|
                   "unencoded" ,
                   make_tuple [ M.call (|
-                    M.get_name (| globals, "nibble_list_to_compact" |),
+                    M.get_name (| globals, locals_stack, "nibble_list_to_compact" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "node" |), "key_segment" |);
+                      M.get_field (| M.get_name (| globals, locals_stack, "node" |), "key_segment" |);
                       Constant.bool false
                     ],
                     make_dict []
-                  |); M.get_field (| M.get_name (| globals, "node" |), "subnode" |) ]
+                  |); M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnode" |) ]
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -282,10 +285,10 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* if *)
                   M.if_then_else (|
                     M.call (|
-                      M.get_name (| globals, "isinstance" |),
+                      M.get_name (| globals, locals_stack, "isinstance" |),
                       make_list [
-                        M.get_name (| globals, "node" |);
-                        M.get_name (| globals, "BranchNode" |)
+                        M.get_name (| globals, locals_stack, "node" |);
+                        M.get_name (| globals, locals_stack, "BranchNode" |)
                       ],
                       make_dict []
                     |),
@@ -294,9 +297,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                     let _ := M.assign_local (|
                       "unencoded" ,
                       BinOp.add (|
-                        M.get_field (| M.get_name (| globals, "node" |), "subnodes" |),
+                        M.get_field (| M.get_name (| globals, locals_stack, "node" |), "subnodes" |),
                         make_list [
-                          M.get_field (| M.get_name (| globals, "node" |), "value" |)
+                          M.get_field (| M.get_name (| globals, locals_stack, "node" |), "value" |)
                         ]
                       |)
                     |) in
@@ -304,7 +307,7 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
                   (* else *)
                   )), ltac:(M.monadic (
                     let _ := M.raise (| Some (M.call (|
-                      M.get_name (| globals, "AssertionError" |),
+                      M.get_name (| globals, locals_stack, "AssertionError" |),
                       make_list [
                         Constant.str "(* At expr: unsupported node type: JoinedStr *)"
                       ],
@@ -321,9 +324,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "encoded" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
         make_list [
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         ],
         make_dict []
       |)
@@ -333,9 +336,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |),
@@ -344,16 +347,16 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "unencoded" |)
+          M.get_name (| globals, locals_stack, "unencoded" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
-              M.get_name (| globals, "encoded" |)
+              M.get_name (| globals, locals_stack, "encoded" |)
             ],
             make_dict []
           |)
@@ -363,8 +366,9 @@ Definition encode_internal_node : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition encode_node : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "node"; "storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "node"; "storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Encode a Node for storage in the Merkle Trie.
 
@@ -374,25 +378,25 @@ Definition encode_node : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "node" |);
-            M.get_name (| globals, "Account" |)
+            M.get_name (| globals, locals_stack, "node" |);
+            M.get_name (| globals, locals_stack, "Account" |)
           ],
           make_dict []
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "storage_root" |),
+    M.get_name (| globals, locals_stack, "storage_root" |),
     Constant.None_
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "encode_account" |),
+            M.get_name (| globals, locals_stack, "encode_account" |),
             make_list [
-              M.get_name (| globals, "node" |);
-              M.get_name (| globals, "storage_root" |)
+              M.get_name (| globals, locals_stack, "node" |);
+              M.get_name (| globals, locals_stack, "storage_root" |)
             ],
             make_dict []
           |)
@@ -404,10 +408,10 @@ Definition encode_node : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "node" |);
-                make_tuple [ M.get_name (| globals, "Transaction" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "U256" |) ]
+                M.get_name (| globals, locals_stack, "node" |);
+                make_tuple [ M.get_name (| globals, locals_stack, "Transaction" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "U256" |) ]
               ],
               make_dict []
             |),
@@ -415,13 +419,13 @@ Definition encode_node : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "cast" |),
+                    M.get_name (| globals, locals_stack, "cast" |),
                     make_list [
-                      M.get_field (| M.get_name (| globals, "rlp" |), "RLP" |);
-                      M.get_name (| globals, "node" |)
+                      M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "RLP" |);
+                      M.get_name (| globals, locals_stack, "node" |)
                     ],
                     make_dict []
                   |)
@@ -436,27 +440,27 @@ Definition encode_node : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 M.call (|
-                  M.get_name (| globals, "isinstance" |),
+                  M.get_name (| globals, locals_stack, "isinstance" |),
                   make_list [
-                    M.get_name (| globals, "node" |);
-                    M.get_name (| globals, "Bytes" |)
+                    M.get_name (| globals, locals_stack, "node" |);
+                    M.get_name (| globals, locals_stack, "Bytes" |)
                   ],
                   make_dict []
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.return_ (|
-                  M.get_name (| globals, "node" |)
+                  M.get_name (| globals, locals_stack, "node" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.return_ (|
                   M.call (|
-                    M.get_field (| M.get_name (| globals, "previous_trie" |), "encode_node" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "previous_trie" |), "encode_node" |),
                     make_list [
-                      M.get_name (| globals, "node" |);
-                      M.get_name (| globals, "storage_root" |)
+                      M.get_name (| globals, locals_stack, "node" |);
+                      M.get_name (| globals, locals_stack, "storage_root" |)
                     ],
                     make_dict []
                   |)
@@ -480,8 +484,9 @@ Definition Trie : Value.t :=
     ].
 
 Definition copy_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a copy of `trie`. Since only frozen objects may be stored in tries,
     the contents are reused.
@@ -498,14 +503,14 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Trie" |),
+        M.get_name (| globals, locals_stack, "Trie" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "trie" |), "secured" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |);
           M.call (|
-            M.get_field (| M.get_name (| globals, "copy" |), "copy" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "copy" |), "copy" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             ],
             make_dict []
           |)
@@ -516,8 +521,9 @@ Definition copy_trie : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition trie_set : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores an item in a Merkle Trie.
 
@@ -537,8 +543,8 @@ Definition trie_set : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         |),
       (* then *)
       ltac:(M.monadic (
@@ -546,14 +552,14 @@ Definition trie_set : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.in_ (|
-              M.get_name (| globals, "key" |),
-              M.get_field (| M.get_name (| globals, "trie" |), "_data" |)
+              M.get_name (| globals, locals_stack, "key" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |)
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.delete (| M.get_subscript (|
-    M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-    M.get_name (| globals, "key" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+    M.get_name (| globals, locals_stack, "key" |)
   |) |) in
             M.pure Constant.None_
           (* else *)
@@ -565,18 +571,19 @@ Definition trie_set : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign (|
           M.get_subscript (|
-            M.get_field (| M.get_name (| globals, "trie" |), "_data" |),
-            M.get_name (| globals, "key" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |),
+            M.get_name (| globals, locals_stack, "key" |)
           |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       )) |) in
     M.pure Constant.None_)).
 
 Definition trie_get : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "key" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "key" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Gets an item from the Merkle Trie.
 
@@ -596,10 +603,10 @@ Definition trie_get : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "get" |),
+        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "get" |),
         make_list [
-          M.get_name (| globals, "key" |);
-          M.get_field (| M.get_name (| globals, "trie" |), "default" |)
+          M.get_name (| globals, locals_stack, "key" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "default" |)
         ],
         make_dict []
       |)
@@ -607,21 +614,22 @@ Definition trie_get : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition common_prefix_length : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "a"; "b" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "a"; "b" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Find the longest common prefix of two sequences.
     " in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "a" |)
+            M.get_name (| globals, locals_stack, "a" |)
           ],
           make_dict []
         |)
@@ -634,11 +642,11 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             M.if_then_else (|
               BoolOp.or (|
                 Compare.gt_e (|
-                  M.get_name (| globals, "i" |),
+                  M.get_name (| globals, locals_stack, "i" |),
                   M.call (|
-                    M.get_name (| globals, "len" |),
+                    M.get_name (| globals, locals_stack, "len" |),
                     make_list [
-                      M.get_name (| globals, "b" |)
+                      M.get_name (| globals, locals_stack, "b" |)
                     ],
                     make_dict []
                   |)
@@ -646,12 +654,12 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
                 ltac:(M.monadic (
                   Compare.not_eq (|
                     M.get_subscript (|
-                      M.get_name (| globals, "a" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "a" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |),
                     M.get_subscript (|
-                      M.get_name (| globals, "b" |),
-                      M.get_name (| globals, "i" |)
+                      M.get_name (| globals, locals_stack, "b" |),
+                      M.get_name (| globals, locals_stack, "i" |)
                     |)
                   |)
                 ))
@@ -659,7 +667,7 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
             (* then *)
             ltac:(M.monadic (
               let _ := M.return_ (|
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "i" |)
               |) in
               M.pure Constant.None_
             (* else *)
@@ -674,9 +682,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "a" |)
+          M.get_name (| globals, locals_stack, "a" |)
         ],
         make_dict []
       |)
@@ -684,8 +692,9 @@ Definition common_prefix_length : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "x"; "is_leaf" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "x"; "is_leaf" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Compresses nibble-list into a standard byte array with a flag.
 
@@ -722,7 +731,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "compact" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [],
         make_dict []
       |)
@@ -733,9 +742,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
         Compare.eq (|
           BinOp.mod_ (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
@@ -746,13 +755,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.mult (|
         Constant.int 16,
         BinOp.mult (|
           Constant.int 2,
-          M.get_name (| globals, "is_leaf" |)
+          M.get_name (| globals, locals_stack, "is_leaf" |)
         |)
       |)
     ],
@@ -760,15 +769,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -778,20 +787,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -809,7 +818,7 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
@@ -817,13 +826,13 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
           BinOp.add (|
             BinOp.mult (|
               Constant.int 2,
-              M.get_name (| globals, "is_leaf" |)
+              M.get_name (| globals, locals_stack, "is_leaf" |)
             |),
             Constant.int 1
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           Constant.int 0
         |)
       |)
@@ -832,15 +841,15 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
   |) in
         let _ :=
           M.for_ (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 1;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "x" |)
+            M.get_name (| globals, locals_stack, "x" |)
           ],
           make_dict []
         |);
@@ -850,20 +859,20 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     |),
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "compact" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "compact" |), "append" |),
     make_list [
       BinOp.add (|
         BinOp.mult (|
           Constant.int 16,
           M.get_subscript (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "i" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "i" |)
           |)
         |),
         M.get_subscript (|
-          M.get_name (| globals, "x" |),
+          M.get_name (| globals, locals_stack, "x" |),
           BinOp.add (|
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "i" |),
             Constant.int 1
           |)
         |)
@@ -881,9 +890,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "compact" |)
+          M.get_name (| globals, locals_stack, "compact" |)
         ],
         make_dict []
       |)
@@ -891,8 +900,9 @@ Definition nibble_list_to_compact : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "bytes_" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "bytes_" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a `Bytes` into to a sequence of nibbles (bytes with value < 16).
 
@@ -909,14 +919,14 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "nibble_list" ,
       M.call (|
-        M.get_name (| globals, "bytearray" |),
+        M.get_name (| globals, locals_stack, "bytearray" |),
         make_list [
           BinOp.mult (|
             Constant.int 2,
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "bytes_" |)
+                M.get_name (| globals, locals_stack, "bytes_" |)
               ],
               make_dict []
             |)
@@ -927,26 +937,26 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "byte_index" |); M.get_name (| globals, "byte" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "byte_index" |); M.get_name (| globals, locals_stack, "byte" |) ],
         M.call (|
-      M.get_name (| globals, "enumerate" |),
+      M.get_name (| globals, locals_stack, "enumerate" |),
       make_list [
-        M.get_name (| globals, "bytes_" |)
+        M.get_name (| globals, locals_stack, "bytes_" |)
       ],
       make_dict []
     |),
         ltac:(M.monadic (
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.mult (|
-                M.get_name (| globals, "byte_index" |),
+                M.get_name (| globals, locals_stack, "byte_index" |),
                 Constant.int 2
               |)
             |),
             BinOp.r_shift (|
               BinOp.bit_and (|
-                M.get_name (| globals, "byte" |),
+                M.get_name (| globals, locals_stack, "byte" |),
                 Constant.int 240
               |),
               Constant.int 4
@@ -954,17 +964,17 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
           |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "nibble_list" |),
+              M.get_name (| globals, locals_stack, "nibble_list" |),
               BinOp.add (|
                 BinOp.mult (|
-                  M.get_name (| globals, "byte_index" |),
+                  M.get_name (| globals, locals_stack, "byte_index" |),
                   Constant.int 2
                 |),
                 Constant.int 1
               |)
             |),
             BinOp.bit_and (|
-              M.get_name (| globals, "byte" |),
+              M.get_name (| globals, locals_stack, "byte" |),
               Constant.int 15
             |)
           |) in
@@ -976,9 +986,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
-          M.get_name (| globals, "nibble_list" |)
+          M.get_name (| globals, locals_stack, "nibble_list" |)
         ],
         make_dict []
       |)
@@ -986,8 +996,9 @@ Definition bytes_to_nibble_list : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition _prepare_trie : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Prepares the trie for root calculation. Removes values that are empty,
     hashes the keys (if `secured == True`) and encodes all the nodes.
@@ -1008,9 +1019,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "preimage" |); M.get_name (| globals, "value" |) ],
+        make_tuple [ M.get_name (| globals, locals_stack, "preimage" |); M.get_name (| globals, locals_stack, "value" |) ],
         M.call (|
-      M.get_field (| M.get_field (| M.get_name (| globals, "trie" |), "_data" |), "items" |),
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "_data" |), "items" |),
       make_list [],
       make_dict []
     |),
@@ -1019,25 +1030,25 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               M.call (|
-                M.get_name (| globals, "isinstance" |),
+                M.get_name (| globals, locals_stack, "isinstance" |),
                 make_list [
-                  M.get_name (| globals, "value" |);
-                  M.get_name (| globals, "Account" |)
+                  M.get_name (| globals, locals_stack, "value" |);
+                  M.get_name (| globals, locals_stack, "Account" |)
                 ],
                 make_dict []
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assert (| Compare.is_not (|
-    M.get_name (| globals, "get_storage_root" |),
+    M.get_name (| globals, locals_stack, "get_storage_root" |),
     Constant.None_
   |) |) in
               let _ := M.assign_local (|
                 "address" ,
                 M.call (|
-                  M.get_name (| globals, "Address" |),
+                  M.get_name (| globals, locals_stack, "Address" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1045,13 +1056,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |);
+                    M.get_name (| globals, locals_stack, "value" |);
                     M.call (|
-                      M.get_name (| globals, "get_storage_root" |),
+                      M.get_name (| globals, locals_stack, "get_storage_root" |),
                       make_list [
-                        M.get_name (| globals, "address" |)
+                        M.get_name (| globals, locals_stack, "address" |)
                       ],
                       make_dict []
                     |)
@@ -1065,9 +1076,9 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "encoded_value" ,
                 M.call (|
-                  M.get_name (| globals, "encode_node" |),
+                  M.get_name (| globals, locals_stack, "encode_node" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -1075,13 +1086,13 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
               M.pure Constant.None_
             )) |) in
           let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.not_eq (|
-        M.get_name (| globals, "encoded_value" |),
+        M.get_name (| globals, locals_stack, "encoded_value" |),
         Constant.bytes ""
       |);
-      M.get_name (| globals, "AssertionError" |)
+      M.get_name (| globals, locals_stack, "AssertionError" |)
     ],
     make_dict []
   |) in
@@ -1089,15 +1100,15 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
           let _ :=
             (* if *)
             M.if_then_else (|
-              M.get_field (| M.get_name (| globals, "trie" |), "secured" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "trie" |), "secured" |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
                 M.call (|
-                  M.get_name (| globals, "keccak256" |),
+                  M.get_name (| globals, locals_stack, "keccak256" |),
                   make_list [
-                    M.get_name (| globals, "preimage" |)
+                    M.get_name (| globals, locals_stack, "preimage" |)
                   ],
                   make_dict []
                 |)
@@ -1107,22 +1118,22 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
             )), ltac:(M.monadic (
               let _ := M.assign_local (|
                 "key" ,
-                M.get_name (| globals, "preimage" |)
+                M.get_name (| globals, locals_stack, "preimage" |)
               |) in
               M.pure Constant.None_
             )) |) in
           let _ := M.assign (|
             M.get_subscript (|
-              M.get_name (| globals, "mapped" |),
+              M.get_name (| globals, locals_stack, "mapped" |),
               M.call (|
-                M.get_name (| globals, "bytes_to_nibble_list" |),
+                M.get_name (| globals, locals_stack, "bytes_to_nibble_list" |),
                 make_list [
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 ],
                 make_dict []
               |)
             |),
-            M.get_name (| globals, "encoded_value" |)
+            M.get_name (| globals, locals_stack, "encoded_value" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1131,13 +1142,14 @@ Definition _prepare_trie : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "mapped" |)
+      M.get_name (| globals, locals_stack, "mapped" |)
     |) in
     M.pure Constant.None_)).
 
 Definition root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "trie"; "get_storage_root" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "trie"; "get_storage_root" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes the root of a modified merkle patricia trie (MPT).
 
@@ -1158,10 +1170,10 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "obj" ,
       M.call (|
-        M.get_name (| globals, "_prepare_trie" |),
+        M.get_name (| globals, locals_stack, "_prepare_trie" |),
         make_list [
-          M.get_name (| globals, "trie" |);
-          M.get_name (| globals, "get_storage_root" |)
+          M.get_name (| globals, locals_stack, "trie" |);
+          M.get_name (| globals, locals_stack, "get_storage_root" |)
         ],
         make_dict []
       |)
@@ -1169,14 +1181,14 @@ Definition root : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "root_node" ,
       M.call (|
-        M.get_name (| globals, "encode_internal_node" |),
+        M.get_name (| globals, locals_stack, "encode_internal_node" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "patricialize" |),
+            M.get_name (| globals, locals_stack, "patricialize" |),
             make_list [
-              M.get_name (| globals, "obj" |);
+              M.get_name (| globals, locals_stack, "obj" |);
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
                   Constant.int 0
                 ],
@@ -1194,12 +1206,12 @@ Definition root : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.lt (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1212,12 +1224,12 @@ Definition root : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "keccak256" |),
+            M.get_name (| globals, locals_stack, "keccak256" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
                 make_list [
-                  M.get_name (| globals, "root_node" |)
+                  M.get_name (| globals, locals_stack, "root_node" |)
                 ],
                 make_dict []
               |)
@@ -1229,18 +1241,18 @@ Definition root : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assert (| M.call (|
-    M.get_name (| globals, "isinstance" |),
+    M.get_name (| globals, locals_stack, "isinstance" |),
     make_list [
-      M.get_name (| globals, "root_node" |);
-      M.get_name (| globals, "Bytes" |)
+      M.get_name (| globals, locals_stack, "root_node" |);
+      M.get_name (| globals, locals_stack, "Bytes" |)
     ],
     make_dict []
   |) |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "Root" |),
+            M.get_name (| globals, locals_stack, "Root" |),
             make_list [
-              M.get_name (| globals, "root_node" |)
+              M.get_name (| globals, locals_stack, "root_node" |)
             ],
             make_dict []
           |)
@@ -1250,8 +1262,9 @@ Definition root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition patricialize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "obj"; "level" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "obj"; "level" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Structural composition function.
 
@@ -1275,9 +1288,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1296,12 +1309,12 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "arbitrary_key" ,
       M.call (|
-        M.get_name (| globals, "next" |),
+        M.get_name (| globals, locals_stack, "next" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "iter" |),
+            M.get_name (| globals, locals_stack, "iter" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |)
@@ -1314,9 +1327,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "obj" |)
+              M.get_name (| globals, locals_stack, "obj" |)
             ],
             make_dict []
           |),
@@ -1327,24 +1340,24 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "leaf" ,
           M.call (|
-            M.get_name (| globals, "LeafNode" |),
+            M.get_name (| globals, locals_stack, "LeafNode" |),
             make_list [
               M.slice (|
-                M.get_name (| globals, "arbitrary_key" |),
-                M.get_name (| globals, "level" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |),
+                M.get_name (| globals, locals_stack, "level" |),
                 Constant.None_,
                 Constant.None_
               |);
               M.get_subscript (|
-                M.get_name (| globals, "obj" |),
-                M.get_name (| globals, "arbitrary_key" |)
+                M.get_name (| globals, locals_stack, "obj" |),
+                M.get_name (| globals, locals_stack, "arbitrary_key" |)
               |)
             ],
             make_dict []
           |)
         |) in
         let _ := M.return_ (|
-          M.get_name (| globals, "leaf" |)
+          M.get_name (| globals, locals_stack, "leaf" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1354,8 +1367,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "substring" ,
       M.slice (|
-        M.get_name (| globals, "arbitrary_key" |),
-        M.get_name (| globals, "level" |),
+        M.get_name (| globals, locals_stack, "arbitrary_key" |),
+        M.get_name (| globals, locals_stack, "level" |),
         Constant.None_,
         Constant.None_
       |)
@@ -1363,31 +1376,31 @@ Definition patricialize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "prefix_length" ,
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "substring" |)
+          M.get_name (| globals, locals_stack, "substring" |)
         ],
         make_dict []
       |)
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ := M.assign_local (|
             "prefix_length" ,
             M.call (|
-              M.get_name (| globals, "min" |),
+              M.get_name (| globals, locals_stack, "min" |),
               make_list [
-                M.get_name (| globals, "prefix_length" |);
+                M.get_name (| globals, locals_stack, "prefix_length" |);
                 M.call (|
-                  M.get_name (| globals, "common_prefix_length" |),
+                  M.get_name (| globals, locals_stack, "common_prefix_length" |),
                   make_list [
-                    M.get_name (| globals, "substring" |);
+                    M.get_name (| globals, locals_stack, "substring" |);
                     M.slice (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |),
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |),
                       Constant.None_,
                       Constant.None_
                     |)
@@ -1402,7 +1415,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "prefix_length" |),
+                M.get_name (| globals, locals_stack, "prefix_length" |),
                 Constant.int 0
               |),
             (* then *)
@@ -1423,7 +1436,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "prefix_length" |),
+          M.get_name (| globals, locals_stack, "prefix_length" |),
           Constant.int 0
         |),
       (* then *)
@@ -1431,30 +1444,30 @@ Definition patricialize : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "prefix" ,
           M.slice (|
-            M.get_name (| globals, "arbitrary_key" |),
-            M.get_name (| globals, "level" |),
+            M.get_name (| globals, locals_stack, "arbitrary_key" |),
+            M.get_name (| globals, locals_stack, "level" |),
             BinOp.add (|
-              M.get_name (| globals, "level" |),
-              M.get_name (| globals, "prefix_length" |)
+              M.get_name (| globals, locals_stack, "level" |),
+              M.get_name (| globals, locals_stack, "prefix_length" |)
             |),
             Constant.None_
           |)
         |) in
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "ExtensionNode" |),
+            M.get_name (| globals, locals_stack, "ExtensionNode" |),
             make_list [
-              M.get_name (| globals, "prefix" |);
+              M.get_name (| globals, locals_stack, "prefix" |);
               M.call (|
-                M.get_name (| globals, "encode_internal_node" |),
+                M.get_name (| globals, locals_stack, "encode_internal_node" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "patricialize" |),
+                    M.get_name (| globals, locals_stack, "patricialize" |),
                     make_list [
-                      M.get_name (| globals, "obj" |);
+                      M.get_name (| globals, locals_stack, "obj" |);
                       BinOp.add (|
-                        M.get_name (| globals, "level" |),
-                        M.get_name (| globals, "prefix_length" |)
+                        M.get_name (| globals, locals_stack, "level" |),
+                        M.get_name (| globals, locals_stack, "prefix_length" |)
                       |)
                     ],
                     make_dict []
@@ -1474,9 +1487,9 @@ Definition patricialize : Value.t -> Value.t -> M :=
 (* At stmt: unsupported node type: AnnAssign *)
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 16
       ],
@@ -1484,7 +1497,7 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "branches" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "branches" |), "append" |),
     make_list [
       Constant.str "(* At expr: unsupported node type: Dict *)"
     ],
@@ -1502,21 +1515,21 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "key" |),
-        M.get_name (| globals, "obj" |),
+        M.get_name (| globals, locals_stack, "key" |),
+        M.get_name (| globals, locals_stack, "obj" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "key" |)
+                    M.get_name (| globals, locals_stack, "key" |)
                   ],
                   make_dict []
                 |),
-                M.get_name (| globals, "level" |)
+                M.get_name (| globals, locals_stack, "level" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -1524,19 +1537,19 @@ Definition patricialize : Value.t -> Value.t -> M :=
                 (* if *)
                 M.if_then_else (|
                   M.call (|
-                    M.get_name (| globals, "isinstance" |),
+                    M.get_name (| globals, locals_stack, "isinstance" |),
                     make_list [
                       M.get_subscript (|
-                        M.get_name (| globals, "obj" |),
-                        M.get_name (| globals, "key" |)
+                        M.get_name (| globals, locals_stack, "obj" |),
+                        M.get_name (| globals, locals_stack, "key" |)
                       |);
-                      make_tuple [ M.get_name (| globals, "Account" |); M.get_name (| globals, "Receipt" |); M.get_name (| globals, "Uint" |) ]
+                      make_tuple [ M.get_name (| globals, locals_stack, "Account" |); M.get_name (| globals, locals_stack, "Receipt" |); M.get_name (| globals, locals_stack, "Uint" |) ]
                     ],
                     make_dict []
                   |),
                 (* then *)
                 ltac:(M.monadic (
-                  let _ := M.raise (| Some (M.get_name (| globals, "AssertionError" |)) |) in
+                  let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "AssertionError" |)) |) in
                   M.pure Constant.None_
                 (* else *)
                 )), ltac:(M.monadic (
@@ -1545,8 +1558,8 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign_local (|
                 "value" ,
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1555,17 +1568,17 @@ Definition patricialize : Value.t -> Value.t -> M :=
               let _ := M.assign (|
                 M.get_subscript (|
                   M.get_subscript (|
-                    M.get_name (| globals, "branches" |),
+                    M.get_name (| globals, locals_stack, "branches" |),
                     M.get_subscript (|
-                      M.get_name (| globals, "key" |),
-                      M.get_name (| globals, "level" |)
+                      M.get_name (| globals, locals_stack, "key" |),
+                      M.get_name (| globals, locals_stack, "level" |)
                     |)
                   |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "key" |)
                 |),
                 M.get_subscript (|
-                  M.get_name (| globals, "obj" |),
-                  M.get_name (| globals, "key" |)
+                  M.get_name (| globals, locals_stack, "obj" |),
+                  M.get_name (| globals, locals_stack, "key" |)
                 |)
               |) in
               M.pure Constant.None_
@@ -1578,10 +1591,10 @@ Definition patricialize : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "BranchNode" |),
+        M.get_name (| globals, locals_stack, "BranchNode" |),
         make_list [
           Constant.str "(* At expr: unsupported node type: ListComp *)";
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/utils/__init__.v b/CoqOfPython/ethereum/tangerine_whistle/utils/__init__.v
index c4428f6..d60c8ff 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/utils/__init__.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.utils.__init__".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/tangerine_whistle/utils/address.v b/CoqOfPython/ethereum/tangerine_whistle/utils/address.v
index e130a74..53b2410 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/utils/address.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/utils/address.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.utils.address".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.utils.address".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_tangerine_whistle_fork_types_imports_Address :
   IsImported globals "ethereum.tangerine_whistle.fork_types" "Address".
 
 Definition to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert a Uint or U256 value to a valid address (20 bytes).
 
@@ -56,11 +59,11 @@ Definition to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.slice (|
             M.call (|
-              M.get_field (| M.get_name (| globals, "data" |), "to_be_bytes32" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "data" |), "to_be_bytes32" |),
               make_list [],
               make_dict []
             |),
@@ -75,8 +78,9 @@ Definition to_address : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition compute_contract_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "address"; "nonce" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "address"; "nonce" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Computes address of the new account that needs to be created.
 
@@ -96,14 +100,14 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "computed_address" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "rlp" |), "encode" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "rlp" |), "encode" |),
             make_list [
               make_list [
-                M.get_name (| globals, "address" |);
-                M.get_name (| globals, "nonce" |)
+                M.get_name (| globals, locals_stack, "address" |);
+                M.get_name (| globals, locals_stack, "nonce" |)
               ]
             ],
             make_dict []
@@ -115,7 +119,7 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "canonical_address" ,
       M.slice (|
-        M.get_name (| globals, "computed_address" |),
+        M.get_name (| globals, locals_stack, "computed_address" |),
         UnOp.sub (| Constant.int 20 |),
         Constant.None_,
         Constant.None_
@@ -124,9 +128,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "canonical_address" |);
+          M.get_name (| globals, locals_stack, "canonical_address" |);
           Constant.int 20
         ],
         make_dict []
@@ -134,9 +138,9 @@ Definition compute_contract_address : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
-          M.get_name (| globals, "padded_address" |)
+          M.get_name (| globals, locals_stack, "padded_address" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/utils/hexadecimal.v b/CoqOfPython/ethereum/tangerine_whistle/utils/hexadecimal.v
index 0079ced..d556869 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_tangerine_whistle_fork_types_imports_Root :
   IsImported globals "ethereum.tangerine_whistle.fork_types" "Root".
 
 Definition hex_to_root : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to trie root.
 
@@ -46,15 +49,15 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Root" |),
+        M.get_name (| globals, locals_stack, "Root" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -68,8 +71,9 @@ Definition hex_to_root : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bloom : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bloom.
 
@@ -85,15 +89,15 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bloom" |),
+        M.get_name (| globals, locals_stack, "Bloom" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -107,8 +111,9 @@ Definition hex_to_bloom : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Address (20 bytes).
 
@@ -124,16 +129,16 @@ Definition hex_to_address : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Address" |),
+        M.get_name (| globals, locals_stack, "Address" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
diff --git a/CoqOfPython/ethereum/tangerine_whistle/utils/message.v b/CoqOfPython/ethereum/tangerine_whistle/utils/message.v
index 8382bfd..d1df2f2 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/utils/message.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/utils/message.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.utils.message".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.utils.message".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_tangerine_whistle_utils_address_imports_compute_contract_address
   IsImported globals "ethereum.tangerine_whistle.utils.address" "compute_contract_address".
 
 Definition prepare_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "caller"; "target"; "value"; "data"; "gas"; "env"; "code_address"; "should_transfer_value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Execute a transaction against the provided environment.
 
@@ -82,10 +85,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "isinstance" |),
+          M.get_name (| globals, locals_stack, "isinstance" |),
           make_list [
-            M.get_name (| globals, "target" |);
-            M.get_name (| globals, "Bytes0" |)
+            M.get_name (| globals, locals_stack, "target" |);
+            M.get_name (| globals, locals_stack, "Bytes0" |)
           ],
           make_dict []
         |),
@@ -94,20 +97,20 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "current_target" ,
           M.call (|
-            M.get_name (| globals, "compute_contract_address" |),
+            M.get_name (| globals, locals_stack, "compute_contract_address" |),
             make_list [
-              M.get_name (| globals, "caller" |);
+              M.get_name (| globals, locals_stack, "caller" |);
               BinOp.sub (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "get_account" |),
+                  M.get_name (| globals, locals_stack, "get_account" |),
                   make_list [
-                    M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                    M.get_name (| globals, "caller" |)
+                    M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                    M.get_name (| globals, locals_stack, "caller" |)
                   ],
                   make_dict []
                 |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "U256" |),
+                  M.get_name (| globals, locals_stack, "U256" |),
                   make_list [
                     Constant.int 1
                   ],
@@ -121,7 +124,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "msg_data" ,
           M.call (|
-            M.get_name (| globals, "Bytes" |),
+            M.get_name (| globals, locals_stack, "Bytes" |),
             make_list [
               Constant.bytes ""
             ],
@@ -130,7 +133,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
         |) in
         let _ := M.assign_local (|
           "code" ,
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -139,10 +142,10 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "isinstance" |),
+              M.get_name (| globals, locals_stack, "isinstance" |),
               make_list [
-                M.get_name (| globals, "target" |);
-                M.get_name (| globals, "Address" |)
+                M.get_name (| globals, locals_stack, "target" |);
+                M.get_name (| globals, locals_stack, "Address" |)
               ],
               make_dict []
             |),
@@ -150,19 +153,19 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "current_target" ,
-              M.get_name (| globals, "target" |)
+              M.get_name (| globals, locals_stack, "target" |)
             |) in
             let _ := M.assign_local (|
               "msg_data" ,
-              M.get_name (| globals, "data" |)
+              M.get_name (| globals, locals_stack, "data" |)
             |) in
             let _ := M.assign_local (|
               "code" ,
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "env" |), "state" |);
-                  M.get_name (| globals, "target" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "target" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -171,14 +174,14 @@ Definition prepare_message : Value.t -> Value.t -> M :=
               (* if *)
               M.if_then_else (|
                 Compare.is (|
-                  M.get_name (| globals, "code_address" |),
+                  M.get_name (| globals, locals_stack, "code_address" |),
                   Constant.None_
                 |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.assign_local (|
                   "code_address" ,
-                  M.get_name (| globals, "target" |)
+                  M.get_name (| globals, locals_stack, "target" |)
                 |) in
                 M.pure Constant.None_
               (* else *)
@@ -189,7 +192,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.raise (| Some (M.call (|
-              M.get_name (| globals, "AssertionError" |),
+              M.get_name (| globals, locals_stack, "AssertionError" |),
               make_list [
                 Constant.str "Target must be address or empty bytes"
               ],
@@ -201,7 +204,7 @@ Definition prepare_message : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/__init__.v b/CoqOfPython/ethereum/tangerine_whistle/vm/__init__.v
index fb5763a..27b6aff 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/__init__.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.__init__".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,8 +90,9 @@ Definition Evm : Value.t :=
     ].
 
 Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of a successful `child_evm` into the parent `evm`.
 
@@ -102,31 +105,32 @@ Definition incorporate_child_on_success : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "logs" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "logs" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "refund_counter" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "refund_counter" |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "update" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "child_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
     M.pure Constant.None_)).
 
 Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "child_evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "child_evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
 
@@ -139,7 +143,7 @@ Definition incorporate_child_on_error : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_field (| M.get_name (| globals, "child_evm" |), "gas_left" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "gas_left" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/exceptions.v b/CoqOfPython/ethereum/tangerine_whistle/vm/exceptions.v
index 97898c1..2f409fe 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/exceptions.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/exceptions.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.exceptions".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.exceptions".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -69,22 +71,23 @@ Definition InvalidOpcode : Value.t :=
     [
       (
         "__init__",
-        fun (args kwargs : Value.t) => ltac:(M.monadic (
-          let _ := M.set_locals (| args, kwargs, [ "self"; "code" ] |) in
+        fun (args kwargs : Value.t) =>
+          let- locals_stack := M.create_locals locals_stack args kwargs [ "self"; "code" ] in
+          ltac:(M.monadic (
           let _ := M.call (|
     M.get_field (| M.call (|
-      M.get_name (| globals, "super" |),
+      M.get_name (| globals, locals_stack, "super" |),
       make_list [],
       make_dict []
     |), "__init__" |),
     make_list [
-      M.get_name (| globals, "code" |)
+      M.get_name (| globals, locals_stack, "code" |)
     ],
     make_dict []
   |) in
           let _ := M.assign (|
-            M.get_field (| M.get_name (| globals, "self" |), "code" |),
-            M.get_name (| globals, "code" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "self" |), "code" |),
+            M.get_name (| globals, locals_stack, "code" |)
           |) in
           M.pure Constant.None_))
       )
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/gas.v b/CoqOfPython/ethereum/tangerine_whistle/vm/gas.v
index 716b689..82655cc 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/gas.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/gas.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.gas".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.gas".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -46,7 +48,7 @@ Axiom ethereum_tangerine_whistle_vm_exceptions_imports_OutOfGasError :
 
 Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 1
     ],
@@ -56,7 +58,7 @@ Definition GAS_JUMPDEST : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2
     ],
@@ -66,7 +68,7 @@ Definition GAS_BASE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -76,7 +78,7 @@ Definition GAS_VERY_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -86,7 +88,7 @@ Definition GAS_SLOAD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20000
     ],
@@ -96,7 +98,7 @@ Definition GAS_STORAGE_SET : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -106,7 +108,7 @@ Definition GAS_STORAGE_UPDATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15000
     ],
@@ -116,7 +118,7 @@ Definition GAS_STORAGE_CLEAR_REFUND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5
     ],
@@ -126,7 +128,7 @@ Definition GAS_LOW : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -136,7 +138,7 @@ Definition GAS_MID : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -146,7 +148,7 @@ Definition GAS_HIGH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -156,7 +158,7 @@ Definition GAS_EXPONENTIATION : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 10
     ],
@@ -166,7 +168,7 @@ Definition GAS_EXPONENTIATION_PER_BYTE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -176,7 +178,7 @@ Definition GAS_MEMORY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 30
     ],
@@ -186,7 +188,7 @@ Definition GAS_KECCAK256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 6
     ],
@@ -196,7 +198,7 @@ Definition GAS_KECCAK256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -206,7 +208,7 @@ Definition GAS_COPY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 20
     ],
@@ -216,7 +218,7 @@ Definition GAS_BLOCK_HASH : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -226,7 +228,7 @@ Definition GAS_EXTERNAL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 400
     ],
@@ -236,7 +238,7 @@ Definition GAS_BALANCE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -246,7 +248,7 @@ Definition GAS_LOG : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 8
     ],
@@ -256,7 +258,7 @@ Definition GAS_LOG_DATA : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 375
     ],
@@ -266,7 +268,7 @@ Definition GAS_LOG_TOPIC : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 32000
     ],
@@ -276,7 +278,7 @@ Definition GAS_CREATE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 200
     ],
@@ -286,7 +288,7 @@ Definition GAS_CODE_DEPOSIT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 0
     ],
@@ -296,7 +298,7 @@ Definition GAS_ZERO : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 700
     ],
@@ -306,7 +308,7 @@ Definition GAS_CALL : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -316,7 +318,7 @@ Definition GAS_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 9000
     ],
@@ -326,7 +328,7 @@ Definition GAS_CALL_VALUE : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 2300
     ],
@@ -336,7 +338,7 @@ Definition GAS_CALL_STIPEND : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 5000
     ],
@@ -346,7 +348,7 @@ Definition GAS_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 25000
     ],
@@ -356,7 +358,7 @@ Definition GAS_SELF_DESTRUCT_NEW_ACCOUNT : Value.t := M.run ltac:(M.monadic (
 
 Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 24000
     ],
@@ -366,7 +368,7 @@ Definition REFUND_SELF_DESTRUCT : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3000
     ],
@@ -376,7 +378,7 @@ Definition GAS_ECRECOVER : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 60
     ],
@@ -386,7 +388,7 @@ Definition GAS_SHA256 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 12
     ],
@@ -396,7 +398,7 @@ Definition GAS_SHA256_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 600
     ],
@@ -406,7 +408,7 @@ Definition GAS_RIPEMD160 : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 120
     ],
@@ -416,7 +418,7 @@ Definition GAS_RIPEMD160_WORD : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 15
     ],
@@ -426,7 +428,7 @@ Definition GAS_IDENTITY : Value.t := M.run ltac:(M.monadic (
 
 Definition GAS_IDENTITY_WORD : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "Uint" |),
+    M.get_name (| globals, locals_stack, "Uint" |),
     make_list [
       Constant.int 3
     ],
@@ -455,8 +457,9 @@ Definition MessageCallGas : Value.t :=
     ].
 
 Definition charge_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "amount" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "amount" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts `amount` from `evm.gas_left`.
 
@@ -469,13 +472,13 @@ Definition charge_gas : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       M.call (|
-        M.get_name (| globals, "GasAndRefund" |),
+        M.get_name (| globals, locals_stack, "GasAndRefund" |),
         make_list [
-          M.get_name (| globals, "amount" |)
+          M.get_name (| globals, locals_stack, "amount" |)
         ],
         make_dict []
       |)
@@ -486,22 +489,22 @@ Definition charge_gas : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "amount" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "amount" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "OutOfGasError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "OutOfGasError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.sub,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
           M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
-      M.get_name (| globals, "amount" |)
+      M.get_name (| globals, locals_stack, "amount" |)
     ],
     make_dict []
   |)
@@ -511,8 +514,9 @@ Definition charge_gas : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "size_in_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "size_in_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas cost for allocating memory
     to the smallest multiple of 32 bytes,
@@ -532,9 +536,9 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
       "size_in_words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
-            M.get_name (| globals, "size_in_bytes" |)
+            M.get_name (| globals, locals_stack, "size_in_bytes" |)
           ],
           make_dict []
         |),
@@ -544,15 +548,15 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "linear_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "size_in_words" |),
-        M.get_name (| globals, "GAS_MEMORY" |)
+        M.get_name (| globals, locals_stack, "size_in_words" |),
+        M.get_name (| globals, locals_stack, "GAS_MEMORY" |)
       |)
     |) in
     let _ := M.assign_local (|
       "quadratic_cost" ,
       BinOp.floor_div (|
         BinOp.pow (|
-          M.get_name (| globals, "size_in_words" |),
+          M.get_name (| globals, locals_stack, "size_in_words" |),
           Constant.int 2
         |),
         Constant.int 512
@@ -561,16 +565,17 @@ Definition calculate_memory_gas_cost : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "total_gas_cost" ,
       BinOp.add (|
-        M.get_name (| globals, "linear_cost" |),
-        M.get_name (| globals, "quadratic_cost" |)
+        M.get_name (| globals, locals_stack, "linear_cost" |),
+        M.get_name (| globals, locals_stack, "quadratic_cost" |)
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     M.pure Constant.None_)).
 
 Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "extensions" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "extensions" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the gas amount to extend memory
 
@@ -589,7 +594,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size_to_extend" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -599,7 +604,7 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to_be_paid" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -609,12 +614,12 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_size" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "memory" |)
+              M.get_name (| globals, locals_stack, "memory" |)
             ],
             make_dict []
           |)
@@ -624,14 +629,14 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        make_tuple [ M.get_name (| globals, "start_position" |); M.get_name (| globals, "size" |) ],
-        M.get_name (| globals, "extensions" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.get_name (| globals, locals_stack, "size" |) ],
+        M.get_name (| globals, locals_stack, "extensions" |),
         ltac:(M.monadic (
           let _ :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "size" |),
+                M.get_name (| globals, locals_stack, "size" |),
                 Constant.int 0
               |),
             (* then *)
@@ -645,9 +650,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "before_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
-                M.get_name (| globals, "current_size" |)
+                M.get_name (| globals, locals_stack, "current_size" |)
               ],
               make_dict []
             |)
@@ -655,20 +660,20 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "after_size" ,
             M.call (|
-              M.get_name (| globals, "ceil32" |),
+              M.get_name (| globals, locals_stack, "ceil32" |),
               make_list [
                 BinOp.add (|
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "start_position" |)
+                      M.get_name (| globals, locals_stack, "start_position" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
-                      M.get_name (| globals, "size" |)
+                      M.get_name (| globals, locals_stack, "size" |)
                     ],
                     make_dict []
                   |)
@@ -681,8 +686,8 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.lt_e (|
-                M.get_name (| globals, "after_size" |),
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |),
+                M.get_name (| globals, locals_stack, "before_size" |)
               |),
             (* then *)
             ltac:(M.monadic (
@@ -696,16 +701,16 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "size_to_extend",
             BinOp.sub (|
-    M.get_name (| globals, "after_size" |),
-    M.get_name (| globals, "before_size" |)
+    M.get_name (| globals, locals_stack, "after_size" |),
+    M.get_name (| globals, locals_stack, "before_size" |)
   |)
           |) in
           let _ := M.assign_local (|
             "already_paid" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "before_size" |)
+                M.get_name (| globals, locals_stack, "before_size" |)
               ],
               make_dict []
             |)
@@ -713,9 +718,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
           let _ := M.assign_local (|
             "total_cost" ,
             M.call (|
-              M.get_name (| globals, "calculate_memory_gas_cost" |),
+              M.get_name (| globals, locals_stack, "calculate_memory_gas_cost" |),
               make_list [
-                M.get_name (| globals, "after_size" |)
+                M.get_name (| globals, locals_stack, "after_size" |)
               ],
               make_dict []
             |)
@@ -724,13 +729,13 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
             BinOp.add,
             "to_be_paid",
             BinOp.sub (|
-    M.get_name (| globals, "total_cost" |),
-    M.get_name (| globals, "already_paid" |)
+    M.get_name (| globals, locals_stack, "total_cost" |),
+    M.get_name (| globals, locals_stack, "already_paid" |)
   |)
           |) in
           let _ := M.assign_local (|
             "current_size" ,
-            M.get_name (| globals, "after_size" |)
+            M.get_name (| globals, locals_stack, "after_size" |)
           |) in
           M.pure Constant.None_
         )),
@@ -740,10 +745,10 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "ExtendMemory" |),
+        M.get_name (| globals, locals_stack, "ExtendMemory" |),
         make_list [
-          M.get_name (| globals, "to_be_paid" |);
-          M.get_name (| globals, "size_to_extend" |)
+          M.get_name (| globals, locals_stack, "to_be_paid" |);
+          M.get_name (| globals, locals_stack, "size_to_extend" |)
         ],
         make_dict []
       |)
@@ -751,8 +756,9 @@ Definition calculate_gas_extend_memory : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "gas"; "gas_left"; "memory_cost"; "extra_gas"; "call_stipend" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the MessageCallGas (cost and stipend) for
     executing call Opcodes.
@@ -783,13 +789,13 @@ Definition calculate_message_call_gas : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -797,32 +803,32 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "call_stipend" |)
+M.get_name (| globals, locals_stack, "call_stipend" |)
       )) |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas_left" |),
           BinOp.add (|
-            M.get_name (| globals, "extra_gas" |),
-            M.get_name (| globals, "memory_cost" |)
+            M.get_name (| globals, locals_stack, "extra_gas" |),
+            M.get_name (| globals, locals_stack, "memory_cost" |)
           |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.call (|
-            M.get_name (| globals, "MessageCallGas" |),
+            M.get_name (| globals, locals_stack, "MessageCallGas" |),
             make_list [
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |);
               BinOp.add (|
-                M.get_name (| globals, "gas" |),
-                M.get_name (| globals, "call_stipend" |)
+                M.get_name (| globals, locals_stack, "gas" |),
+                M.get_name (| globals, locals_stack, "call_stipend" |)
               |)
             ],
             make_dict []
@@ -836,18 +842,18 @@ M.get_name (| globals, "call_stipend" |)
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "max_message_call_gas" |),
+            M.get_name (| globals, locals_stack, "max_message_call_gas" |),
             make_list [
               BinOp.sub (|
                 BinOp.sub (|
-                  M.get_name (| globals, "gas_left" |),
-                  M.get_name (| globals, "memory_cost" |)
+                  M.get_name (| globals, locals_stack, "gas_left" |),
+                  M.get_name (| globals, locals_stack, "memory_cost" |)
                 |),
-                M.get_name (| globals, "extra_gas" |)
+                M.get_name (| globals, locals_stack, "extra_gas" |)
               |)
             ],
             make_dict []
@@ -858,15 +864,15 @@ M.get_name (| globals, "call_stipend" |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallGas" |),
+        M.get_name (| globals, locals_stack, "MessageCallGas" |),
         make_list [
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "extra_gas" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "extra_gas" |)
           |);
           BinOp.add (|
-            M.get_name (| globals, "gas" |),
-            M.get_name (| globals, "call_stipend" |)
+            M.get_name (| globals, locals_stack, "gas" |),
+            M.get_name (| globals, locals_stack, "call_stipend" |)
           |)
         ],
         make_dict []
@@ -875,8 +881,9 @@ M.get_name (| globals, "call_stipend" |)
     M.pure Constant.None_)).
 
 Definition max_message_call_gas : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "gas" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "gas" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Calculates the maximum gas that is allowed for making a message call
 
@@ -892,9 +899,9 @@ Definition max_message_call_gas : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       BinOp.sub (|
-        M.get_name (| globals, "gas" |),
+        M.get_name (| globals, locals_stack, "gas" |),
         BinOp.floor_div (|
-          M.get_name (| globals, "gas" |),
+          M.get_name (| globals, locals_stack, "gas" |),
           Constant.int 64
         |)
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/__init__.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/__init__.v
index 22a0b88..6e8a81f 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/__init__.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.__init__".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/arithmetic.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/arithmetic.v
index 6908f7e..ef45b8a 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/arithmetic.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.arithmetic".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -51,8 +53,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds the top two elements of the stack together, and pushes the result back
     on the stack.
@@ -66,9 +69,9 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,49 +79,50 @@ Definition add : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_add" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_add" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sub : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Subtracts the top two elements of the stack, and pushes the result back
     on the stack.
@@ -132,9 +136,9 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,49 +146,50 @@ Definition sub : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_sub" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_sub" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mul : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiply the top two elements of the stack, and pushes the result back
     on the stack.
@@ -198,9 +203,9 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -208,49 +213,50 @@ Definition mul : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "x" |), "wrapping_mul" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "x" |), "wrapping_mul" |),
         make_list [
-          M.get_name (| globals, "y" |)
+          M.get_name (| globals, locals_stack, "y" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition div : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Integer division of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -264,9 +270,9 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "dividend" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -274,18 +280,18 @@ Definition div : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "divisor" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -293,7 +299,7 @@ Definition div : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -301,7 +307,7 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -314,30 +320,31 @@ Definition div : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "quotient" ,
           BinOp.floor_div (|
-            M.get_name (| globals, "dividend" |),
-            M.get_name (| globals, "divisor" |)
+            M.get_name (| globals, locals_stack, "dividend" |),
+            M.get_name (| globals, locals_stack, "divisor" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "quotient" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "quotient" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sdiv : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed integer division of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -352,9 +359,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "dividend" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -366,9 +373,9 @@ Definition sdiv : Value.t -> Value.t -> M :=
       "divisor" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -377,10 +384,10 @@ Definition sdiv : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -388,7 +395,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "divisor" |),
+          M.get_name (| globals, locals_stack, "divisor" |),
           Constant.int 0
         |),
       (* then *)
@@ -405,12 +412,12 @@ Definition sdiv : Value.t -> Value.t -> M :=
           M.if_then_else (|
             BoolOp.and (|
               Compare.eq (|
-                M.get_name (| globals, "dividend" |),
-                UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+                M.get_name (| globals, locals_stack, "dividend" |),
+                UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
               |),
               ltac:(M.monadic (
                 Compare.eq (|
-                  M.get_name (| globals, "divisor" |),
+                  M.get_name (| globals, locals_stack, "divisor" |),
                   UnOp.sub (| Constant.int 1 |)
                 |)
               ))
@@ -419,7 +426,7 @@ Definition sdiv : Value.t -> Value.t -> M :=
           ltac:(M.monadic (
             let _ := M.assign_local (|
               "quotient" ,
-              UnOp.sub (| M.get_name (| globals, "U255_CEIL_VALUE" |) |)
+              UnOp.sub (| M.get_name (| globals, locals_stack, "U255_CEIL_VALUE" |) |)
             |) in
             M.pure Constant.None_
           (* else *)
@@ -427,11 +434,11 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "sign" ,
               M.call (|
-                M.get_name (| globals, "get_sign" |),
+                M.get_name (| globals, locals_stack, "get_sign" |),
                 make_list [
                   BinOp.mult (|
-                    M.get_name (| globals, "dividend" |),
-                    M.get_name (| globals, "divisor" |)
+                    M.get_name (| globals, locals_stack, "dividend" |),
+                    M.get_name (| globals, locals_stack, "divisor" |)
                   |)
                 ],
                 make_dict []
@@ -440,19 +447,19 @@ Definition sdiv : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "quotient" ,
               BinOp.mult (|
-                M.get_name (| globals, "sign" |),
+                M.get_name (| globals, locals_stack, "sign" |),
                 BinOp.floor_div (|
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "dividend" |)
+                      M.get_name (| globals, locals_stack, "dividend" |)
                     ],
                     make_dict []
                   |),
                   M.call (|
-                    M.get_name (| globals, "abs" |),
+                    M.get_name (| globals, locals_stack, "abs" |),
                     make_list [
-                      M.get_name (| globals, "divisor" |)
+                      M.get_name (| globals, locals_stack, "divisor" |)
                     ],
                     make_dict []
                   |)
@@ -464,13 +471,13 @@ Definition sdiv : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "quotient" |)
+          M.get_name (| globals, locals_stack, "quotient" |)
         ],
         make_dict []
       |)
@@ -479,14 +486,15 @@ Definition sdiv : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mod_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo remainder of the top two elements of the stack. Pushes the result
     back on the stack.
@@ -500,9 +508,9 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -510,18 +518,18 @@ Definition mod_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -529,7 +537,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -537,7 +545,7 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -550,30 +558,31 @@ Definition mod_ : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "remainder" ,
           BinOp.mod_ (|
-            M.get_name (| globals, "x" |),
-            M.get_name (| globals, "y" |)
+            M.get_name (| globals, locals_stack, "x" |),
+            M.get_name (| globals, locals_stack, "y" |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "remainder" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "remainder" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition smod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed modulo remainder of the top two elements of the stack. Pushes the
     result back on the stack.
@@ -588,9 +597,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "x" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -602,9 +611,9 @@ Definition smod : Value.t -> Value.t -> M :=
       "y" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -613,10 +622,10 @@ Definition smod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -624,7 +633,7 @@ Definition smod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "y" |),
+          M.get_name (| globals, locals_stack, "y" |),
           Constant.int 0
         |),
       (* then *)
@@ -640,24 +649,24 @@ Definition smod : Value.t -> Value.t -> M :=
           "remainder" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "get_sign" |),
+              M.get_name (| globals, locals_stack, "get_sign" |),
               make_list [
-                M.get_name (| globals, "x" |)
+                M.get_name (| globals, locals_stack, "x" |)
               ],
               make_dict []
             |),
             BinOp.mod_ (|
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "x" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "abs" |),
+                M.get_name (| globals, locals_stack, "abs" |),
                 make_list [
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "y" |)
                 ],
                 make_dict []
               |)
@@ -667,13 +676,13 @@ Definition smod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_signed" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_signed" |),
         make_list [
-          M.get_name (| globals, "remainder" |)
+          M.get_name (| globals, locals_stack, "remainder" |)
         ],
         make_dict []
       |)
@@ -682,14 +691,15 @@ Definition smod : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition addmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo addition of the top 2 elements with the 3rd element. Pushes the
     result back on the stack.
@@ -703,12 +713,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -719,12 +729,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -735,12 +745,12 @@ Definition addmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -749,10 +759,10 @@ Definition addmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -760,7 +770,7 @@ Definition addmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -768,7 +778,7 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -781,14 +791,14 @@ Definition addmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.add (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -797,23 +807,24 @@ Definition addmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mulmod : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Modulo multiplication of the top 2 elements with the 3rd element. Pushes
     the result back on the stack.
@@ -827,12 +838,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -843,12 +854,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -859,12 +870,12 @@ Definition mulmod : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "z" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -873,10 +884,10 @@ Definition mulmod : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -884,7 +895,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "z" |),
+          M.get_name (| globals, locals_stack, "z" |),
           Constant.int 0
         |),
       (* then *)
@@ -892,7 +903,7 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -905,14 +916,14 @@ Definition mulmod : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               BinOp.mod_ (|
                 BinOp.mult (|
-                  M.get_name (| globals, "x" |),
-                  M.get_name (| globals, "y" |)
+                  M.get_name (| globals, locals_stack, "x" |),
+                  M.get_name (| globals, locals_stack, "y" |)
                 |),
-                M.get_name (| globals, "z" |)
+                M.get_name (| globals, locals_stack, "z" |)
               |)
             ],
             make_dict []
@@ -921,23 +932,24 @@ Definition mulmod : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition exp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Exponential operation of the top 2 elements. Pushes the result back on
     the stack.
@@ -951,12 +963,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "base" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -967,12 +979,12 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -983,7 +995,7 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "exponent_bits" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "exponent" |), "bit_length" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "exponent" |), "bit_length" |),
         make_list [],
         make_dict []
       |)
@@ -992,21 +1004,21 @@ Definition exp : Value.t -> Value.t -> M :=
       "exponent_bytes" ,
       BinOp.floor_div (|
         BinOp.add (|
-          M.get_name (| globals, "exponent_bits" |),
+          M.get_name (| globals, locals_stack, "exponent_bits" |),
           Constant.int 7
         |),
         Constant.int 8
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_EXPONENTIATION" |),
+        M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_EXPONENTIATION_PER_BYTE" |),
-          M.get_name (| globals, "exponent_bytes" |)
+          M.get_name (| globals, locals_stack, "GAS_EXPONENTIATION_PER_BYTE" |),
+          M.get_name (| globals, locals_stack, "exponent_bytes" |)
         |)
       |)
     ],
@@ -1015,14 +1027,14 @@ Definition exp : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pow" |),
+            M.get_name (| globals, locals_stack, "pow" |),
             make_list [
-              M.get_name (| globals, "base" |);
-              M.get_name (| globals, "exponent" |);
-              M.get_name (| globals, "U256_CEIL_VALUE" |)
+              M.get_name (| globals, locals_stack, "base" |);
+              M.get_name (| globals, locals_stack, "exponent" |);
+              M.get_name (| globals, locals_stack, "U256_CEIL_VALUE" |)
             ],
             make_dict []
           |)
@@ -1031,23 +1043,24 @@ Definition exp : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signextend : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Sign extend operation. In other words, extend a signed number which
     fits in N bytes to 32 bytes.
@@ -1061,9 +1074,9 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_num" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1071,18 +1084,18 @@ Definition signextend : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_LOW" |)
     ],
     make_dict []
   |) in
@@ -1090,14 +1103,14 @@ Definition signextend : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_name (| globals, "byte_num" |),
+          M.get_name (| globals, locals_stack, "byte_num" |),
           Constant.int 31
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "result" ,
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1105,10 +1118,10 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.call (|
-            M.get_name (| globals, "bytes" |),
+            M.get_name (| globals, locals_stack, "bytes" |),
             make_list [
               M.call (|
-                M.get_field (| M.get_name (| globals, "value" |), "to_be_bytes32" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "value" |), "to_be_bytes32" |),
                 make_list [],
                 make_dict []
               |)
@@ -1119,13 +1132,13 @@ Definition signextend : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "value_bytes" ,
           M.slice (|
-            M.get_name (| globals, "value_bytes" |),
+            M.get_name (| globals, locals_stack, "value_bytes" |),
             BinOp.sub (|
               Constant.int 31,
               M.call (|
-                M.get_name (| globals, "int" |),
+                M.get_name (| globals, locals_stack, "int" |),
                 make_list [
-                  M.get_name (| globals, "byte_num" |)
+                  M.get_name (| globals, locals_stack, "byte_num" |)
                 ],
                 make_dict []
               |)
@@ -1138,7 +1151,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           "sign_bit" ,
           BinOp.r_shift (|
             M.get_subscript (|
-              M.get_name (| globals, "value_bytes" |),
+              M.get_name (| globals, locals_stack, "value_bytes" |),
               Constant.int 0
             |),
             Constant.int 7
@@ -1148,7 +1161,7 @@ Definition signextend : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "sign_bit" |),
+              M.get_name (| globals, locals_stack, "sign_bit" |),
               Constant.int 0
             |),
           (* then *)
@@ -1156,9 +1169,9 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
-                  M.get_name (| globals, "value_bytes" |)
+                  M.get_name (| globals, locals_stack, "value_bytes" |)
                 ],
                 make_dict []
               |)
@@ -1171,7 +1184,7 @@ Definition signextend : Value.t -> Value.t -> M :=
               BinOp.sub (|
                 Constant.int 32,
                 BinOp.add (|
-                  M.get_name (| globals, "byte_num" |),
+                  M.get_name (| globals, locals_stack, "byte_num" |),
                   Constant.int 1
                 |)
               |)
@@ -1179,22 +1192,22 @@ Definition signextend : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "result" ,
               M.call (|
-                M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
                 make_list [
                   BinOp.add (|
                     M.call (|
-                      M.get_name (| globals, "bytearray" |),
+                      M.get_name (| globals, locals_stack, "bytearray" |),
                       make_list [
                         BinOp.mult (|
                           make_list [
                             Constant.int 255
                           ],
-                          M.get_name (| globals, "num_bytes_prepend" |)
+                          M.get_name (| globals, locals_stack, "num_bytes_prepend" |)
                         |)
                       ],
                       make_dict []
                     |),
-                    M.get_name (| globals, "value_bytes" |)
+                    M.get_name (| globals, locals_stack, "value_bytes" |)
                   |)
                 ],
                 make_dict []
@@ -1205,16 +1218,16 @@ Definition signextend : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/bitwise.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/bitwise.v
index b526d4e..e3d76aa 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/bitwise.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/bitwise.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.bitwise".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.bitwise".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition bitwise_and : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise AND operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,42 +62,43 @@ Definition bitwise_and : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_and (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_or : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise OR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -108,9 +112,9 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -118,42 +122,43 @@ Definition bitwise_or : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_or (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_xor : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise XOR operation of the top 2 elements of the stack. Pushes the
     result back on the stack.
@@ -167,9 +172,9 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -177,42 +182,43 @@ Definition bitwise_xor : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "y" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       BinOp.bit_xor (|
-        M.get_name (| globals, "x" |),
-        M.get_name (| globals, "y" |)
+        M.get_name (| globals, locals_stack, "x" |),
+        M.get_name (| globals, locals_stack, "y" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition bitwise_not : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Bitwise NOT operation of the top element of the stack. Pushes the
     result back on the stack.
@@ -226,39 +232,40 @@ Definition bitwise_not : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      UnOp.invert (| M.get_name (| globals, "x" |) |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      UnOp.invert (| M.get_name (| globals, locals_stack, "x" |) |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition get_byte : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     For a word (defined by next top element of the stack), retrieve the
     Nth byte (0-indexed and defined by top element of stack) from the
@@ -273,9 +280,9 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "byte_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -283,18 +290,18 @@ Definition get_byte : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
@@ -302,7 +309,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt_e (|
-          M.get_name (| globals, "byte_index" |),
+          M.get_name (| globals, locals_stack, "byte_index" |),
           Constant.int 32
         |),
       (* then *)
@@ -310,7 +317,7 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -324,15 +331,15 @@ Definition get_byte : Value.t -> Value.t -> M :=
           "extra_bytes_to_right" ,
           BinOp.sub (|
             Constant.int 31,
-            M.get_name (| globals, "byte_index" |)
+            M.get_name (| globals, locals_stack, "byte_index" |)
           |)
         |) in
         let _ := M.assign_local (|
           "word" ,
           BinOp.r_shift (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             BinOp.mult (|
-              M.get_name (| globals, "extra_bytes_to_right" |),
+              M.get_name (| globals, locals_stack, "extra_bytes_to_right" |),
               Constant.int 8
             |)
           |)
@@ -340,16 +347,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "word" ,
           BinOp.bit_and (|
-            M.get_name (| globals, "word" |),
+            M.get_name (| globals, locals_stack, "word" |),
             Constant.int 255
           |)
         |) in
         let _ := M.assign_local (|
           "result" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
-              M.get_name (| globals, "word" |)
+              M.get_name (| globals, locals_stack, "word" |)
             ],
             make_dict []
           |)
@@ -357,16 +364,16 @@ Definition get_byte : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/block.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/block.v
index 22c744e..55ba480 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/block.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/block.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.block".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.block".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition block_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the hash of one of the 256 most recent complete blocks onto the
     stack. The block number to hash is present at the top of the stack.
@@ -51,18 +54,18 @@ Definition block_hash : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "block_number" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BLOCK_HASH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BLOCK_HASH" |)
     ],
     make_dict []
   |) in
@@ -71,14 +74,14 @@ Definition block_hash : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt_e (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-            M.get_name (| globals, "block_number" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+            M.get_name (| globals, locals_stack, "block_number" |)
           |),
           ltac:(M.monadic (
             Compare.gt (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
               BinOp.add (|
-                M.get_name (| globals, "block_number" |),
+                M.get_name (| globals, locals_stack, "block_number" |),
                 Constant.int 256
               |)
             |)
@@ -96,23 +99,23 @@ Definition block_hash : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "hash" ,
           M.get_subscript (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "block_hashes" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "block_hashes" |),
             UnOp.sub (| BinOp.sub (|
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |),
-              M.get_name (| globals, "block_number" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |),
+              M.get_name (| globals, locals_stack, "block_number" |)
             |) |)
           |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -121,14 +124,15 @@ Definition block_hash : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition coinbase : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's beneficiary address (address of the block miner)
     onto the stack.
@@ -144,21 +148,21 @@ Definition coinbase : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "coinbase" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "coinbase" |)
         ],
         make_dict []
       |)
@@ -167,14 +171,15 @@ Definition coinbase : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition timestamp : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's timestamp onto the stack. Here the timestamp
     being referred is actually the unix timestamp in seconds.
@@ -190,31 +195,32 @@ Definition timestamp : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "time" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "time" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition number : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's number onto the stack.
 
@@ -229,21 +235,21 @@ Definition number : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "number" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "number" |)
         ],
         make_dict []
       |)
@@ -252,14 +258,15 @@ Definition number : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition difficulty : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's difficulty onto the stack.
 
@@ -274,21 +281,21 @@ Definition difficulty : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "difficulty" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "difficulty" |)
         ],
         make_dict []
       |)
@@ -297,14 +304,15 @@ Definition difficulty : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_limit : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the current block's gas limit onto the stack.
 
@@ -319,21 +327,21 @@ Definition gas_limit : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_limit" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_limit" |)
         ],
         make_dict []
       |)
@@ -342,7 +350,7 @@ Definition gas_limit : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/comparison.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/comparison.v
index 7e7ac0d..d7aaec2 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/comparison.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/comparison.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.comparison".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.comparison".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is less than the next top element. Pushes the
     result back on the stack.
@@ -49,9 +52,9 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -59,52 +62,53 @@ Definition less_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_less_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed less-than comparison.
 
@@ -118,9 +122,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -132,9 +136,9 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -143,44 +147,45 @@ Definition signed_less_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.lt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is greater than the next top element. Pushes
     the result back on the stack.
@@ -194,9 +199,9 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -204,52 +209,53 @@ Definition greater_than : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition signed_greater_than : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Signed greater-than comparison.
 
@@ -263,9 +269,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "left" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -277,9 +283,9 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       "right" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_signed" |),
@@ -288,44 +294,45 @@ Definition signed_greater_than : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.gt (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition equal : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to the next top element. Pushes
     the result back on the stack.
@@ -339,9 +346,9 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "left" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -349,52 +356,53 @@ Definition equal : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "right" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "left" |),
-            M.get_name (| globals, "right" |)
+            M.get_name (| globals, locals_stack, "left" |),
+            M.get_name (| globals, locals_stack, "right" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition is_zero : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if the top element is equal to 0. Pushes the result back on the
     stack.
@@ -408,28 +416,28 @@ Definition is_zero : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "x" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "result" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Compare.eq (|
-            M.get_name (| globals, "x" |),
+            M.get_name (| globals, locals_stack, "x" |),
             Constant.int 0
           |)
         ],
@@ -437,16 +445,16 @@ Definition is_zero : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "result" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "result" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/control_flow.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/control_flow.v
index 6ba53bf..bb32d47 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/control_flow.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/control_flow.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.control_flow".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.control_flow".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition stop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stop further execution of EVM code.
 
@@ -58,19 +61,20 @@ Definition stop : Value.t -> Value.t -> M :=
     let _ := M.pass (| |) in
     let _ := M.pass (| |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jump : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the location specified by the top of the
     stack.
@@ -84,12 +88,12 @@ Definition jump : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -98,10 +102,10 @@ Definition jump : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_MID" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_MID" |)
     ],
     make_dict []
   |) in
@@ -109,23 +113,23 @@ Definition jump : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "jump_dest" |),
-          M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "jump_dest" |)
+          M.get_name (| globals, locals_stack, "jump_dest" |)
         ],
         make_dict []
       |)
@@ -133,8 +137,9 @@ Definition jump : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition jumpi : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Alter the program counter to the specified location if and only if a
     condition is true. If the condition is not true, then the program counter
@@ -149,12 +154,12 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "jump_dest" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -165,18 +170,18 @@ Definition jumpi : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "conditional_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_HIGH" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_HIGH" |)
     ],
     make_dict []
   |) in
@@ -184,7 +189,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "conditional_value" |),
+          M.get_name (| globals, locals_stack, "conditional_value" |),
           Constant.int 0
         |),
       (* then *)
@@ -192,7 +197,7 @@ Definition jumpi : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "destination" ,
           BinOp.add (|
-            M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
             Constant.int 1
           |)
         |) in
@@ -203,29 +208,29 @@ Definition jumpi : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.not_in (|
-              M.get_name (| globals, "jump_dest" |),
-              M.get_field (| M.get_name (| globals, "evm" |), "valid_jump_destinations" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "valid_jump_destinations" |)
             |),
           (* then *)
           ltac:(M.monadic (
-            let _ := M.raise (| Some (M.get_name (| globals, "InvalidJumpDestError" |)) |) in
+            let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "InvalidJumpDestError" |)) |) in
             M.pure Constant.None_
           (* else *)
           )), ltac:(M.monadic (
             let _ := M.assign_local (|
               "destination" ,
-              M.get_name (| globals, "jump_dest" |)
+              M.get_name (| globals, locals_stack, "jump_dest" |)
             |) in
             M.pure Constant.None_
           )) |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
-          M.get_name (| globals, "destination" |)
+          M.get_name (| globals, locals_stack, "destination" |)
         ],
         make_dict []
       |)
@@ -233,8 +238,9 @@ Definition jumpi : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition pc : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push onto the stack the value of the program counter after reaching the
     current instruction and without increasing it for the next instruction.
@@ -247,21 +253,21 @@ Definition pc : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "pc" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |)
         ],
         make_dict []
       |)
@@ -270,14 +276,15 @@ Definition pc : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gas_left : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the amount of available gas (including the corresponding reduction
     for the cost of this instruction) onto the stack.
@@ -290,21 +297,21 @@ Definition gas_left : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
         ],
         make_dict []
       |)
@@ -313,14 +320,15 @@ Definition gas_left : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition jumpdest : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Mark a valid destination for jumps. This is a noop, present only
     to be used by `JUMP` and `JUMPI` opcodes to verify that their jump is
@@ -334,17 +342,17 @@ Definition jumpdest : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_JUMPDEST" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_JUMPDEST" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/environment.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/environment.v
index 6f5e691..75c6d21 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/environment.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/environment.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.environment".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.environment".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -60,8 +62,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition address : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the current executing account to the stack.
 
@@ -73,21 +76,21 @@ Definition address : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -96,14 +99,15 @@ Definition address : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition balance : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the balance of the given account onto the stack.
 
@@ -116,12 +120,12 @@ Definition balance : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -130,42 +134,43 @@ Definition balance : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BALANCE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BALANCE" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "balance" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "balance" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition origin : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the original transaction sender to the stack.
     The origin address can only be an EOA.
@@ -178,21 +183,21 @@ Definition origin : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "origin" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "origin" |)
         ],
         make_dict []
       |)
@@ -201,14 +206,15 @@ Definition origin : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition caller : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes the address of the caller onto the stack.
 
@@ -220,21 +226,21 @@ Definition caller : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |)
         ],
         make_dict []
       |)
@@ -243,14 +249,15 @@ Definition caller : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callvalue : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the value (in wei) sent with the call onto the stack.
 
@@ -262,31 +269,32 @@ Definition callvalue : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldataload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push a word (32 bytes) of the input data belonging to the current
     environment onto the stack.
@@ -300,30 +308,30 @@ Definition calldataload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "start_index" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "start_index" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -334,13 +342,13 @@ Definition calldataload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
@@ -349,14 +357,15 @@ Definition calldataload : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatasize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of input data in current environment onto the stack.
 
@@ -368,24 +377,24 @@ Definition calldatasize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
             ],
             make_dict []
           |)
@@ -397,14 +406,15 @@ Definition calldatasize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition calldatacopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the input data in current environment to memory.
 
@@ -420,9 +430,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -430,9 +440,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "data_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -440,9 +450,9 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -451,12 +461,12 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -469,76 +479,77 @@ Definition calldatacopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |);
-          M.get_name (| globals, "data_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |);
+          M.get_name (| globals, locals_stack, "data_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of code running in current environment onto the stack.
 
@@ -550,24 +561,24 @@ Definition codesize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |)
             ],
             make_dict []
           |)
@@ -579,14 +590,15 @@ Definition codesize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition codecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of the code in current environment to memory.
 
@@ -602,9 +614,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -612,9 +624,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -622,9 +634,9 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -633,12 +645,12 @@ Definition codecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -651,76 +663,77 @@ Definition codecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_VERY_LOW" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition gasprice : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the gas price used in current environment onto the stack.
 
@@ -732,21 +745,21 @@ Definition gasprice : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "gas_price" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "gas_price" |)
         ],
         make_dict []
       |)
@@ -755,14 +768,15 @@ Definition gasprice : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodesize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the code size of a given account onto the stack.
 
@@ -775,12 +789,12 @@ Definition extcodesize : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -789,26 +803,26 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_EXTERNAL" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "codesize" ,
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
               M.get_field (| M.call (|
-                M.get_name (| globals, "get_account" |),
+                M.get_name (| globals, locals_stack, "get_account" |),
                 make_list [
-                  M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                  M.get_name (| globals, "address" |)
+                  M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                  M.get_name (| globals, locals_stack, "address" |)
                 ],
                 make_dict []
               |), "code" |)
@@ -820,23 +834,24 @@ Definition extcodesize : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "codesize" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "codesize" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition extcodecopy : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Copy a portion of an account's code to memory.
 
@@ -849,12 +864,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -865,9 +880,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -875,9 +890,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -885,9 +900,9 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -896,12 +911,12 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -914,52 +929,52 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "copy_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_COPY" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_COPY" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_EXTERNAL" |),
-          M.get_name (| globals, "copy_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_EXTERNAL" |),
+          M.get_name (| globals, locals_stack, "copy_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "address" |)
         ],
         make_dict []
       |), "code" |)
@@ -967,27 +982,27 @@ Definition extcodecopy : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "code" |);
-          M.get_name (| globals, "code_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "code" |);
+          M.get_name (| globals, locals_stack, "code_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_start_index" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_start_index" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/keccak.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/keccak.v
index d8e8086..252a3f2 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/keccak.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/keccak.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.keccak".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.keccak".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -49,8 +51,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition keccak : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes to the stack the Keccak-256 hash of a region of memory.
 
@@ -66,9 +69,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -87,12 +90,12 @@ Definition keccak : Value.t -> Value.t -> M :=
       "words" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
-                M.get_name (| globals, "size" |)
+                M.get_name (| globals, locals_stack, "size" |)
               ],
               make_dict []
             |)
@@ -105,53 +108,53 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "word_gas_cost" ,
       BinOp.mult (|
-        M.get_name (| globals, "GAS_KECCAK256_WORD" |),
-        M.get_name (| globals, "words" |)
+        M.get_name (| globals, locals_stack, "GAS_KECCAK256_WORD" |),
+        M.get_name (| globals, locals_stack, "words" |)
       |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
-          M.get_name (| globals, "GAS_KECCAK256" |),
-          M.get_name (| globals, "word_gas_cost" |)
+          M.get_name (| globals, locals_stack, "GAS_KECCAK256" |),
+          M.get_name (| globals, locals_stack, "word_gas_cost" |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_index" |);
-          M.get_name (| globals, "size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_index" |);
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
@@ -159,21 +162,21 @@ Definition keccak : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "hash" ,
       M.call (|
-        M.get_name (| globals, "keccak256" |),
+        M.get_name (| globals, locals_stack, "keccak256" |),
         make_list [
-          M.get_name (| globals, "data" |)
+          M.get_name (| globals, locals_stack, "data" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_name (| globals, "hash" |)
+          M.get_name (| globals, locals_stack, "hash" |)
         ],
         make_dict []
       |)
@@ -182,7 +185,7 @@ Definition keccak : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/log.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/log.v
index 45018dd..aa9820a 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/log.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/log.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.log".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.log".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -47,8 +49,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_pop :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "pop".
 
 Definition log_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_topics" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_topics" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -66,9 +69,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_index" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -76,9 +79,9 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -89,11 +92,11 @@ Definition log_n : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "_" |),
+        M.get_name (| globals, locals_stack, "_" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
-        M.get_name (| globals, "num_topics" |)
+        M.get_name (| globals, locals_stack, "num_topics" |)
       ],
       make_dict []
     |),
@@ -102,9 +105,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             "topic" ,
             M.call (|
               M.get_field (| M.call (|
-                M.get_name (| globals, "pop" |),
+                M.get_name (| globals, locals_stack, "pop" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
                 ],
                 make_dict []
               |), "to_be_bytes32" |),
@@ -113,9 +116,9 @@ Definition log_n : Value.t -> Value.t -> M :=
             |)
           |) in
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "topics" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "topics" |), "append" |),
     make_list [
-      M.get_name (| globals, "topic" |)
+      M.get_name (| globals, locals_stack, "topic" |)
     ],
     make_dict []
   |) in
@@ -128,74 +131,74 @@ Definition log_n : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_index" |); M.get_name (| globals, "size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_index" |); M.get_name (| globals, locals_stack, "size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
         BinOp.add (|
           BinOp.add (|
-            M.get_name (| globals, "GAS_LOG" |),
+            M.get_name (| globals, locals_stack, "GAS_LOG" |),
             BinOp.mult (|
-              M.get_name (| globals, "GAS_LOG_DATA" |),
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "GAS_LOG_DATA" |),
+              M.get_name (| globals, locals_stack, "size" |)
             |)
           |),
           BinOp.mult (|
-            M.get_name (| globals, "GAS_LOG_TOPIC" |),
-            M.get_name (| globals, "num_topics" |)
+            M.get_name (| globals, locals_stack, "GAS_LOG_TOPIC" |),
+            M.get_name (| globals, locals_stack, "num_topics" |)
           |)
         |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "log_entry" ,
       M.call (|
-        M.get_name (| globals, "Log" |),
+        M.get_name (| globals, locals_stack, "Log" |),
         make_list [],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "evm" |), "logs" |),
-        make_tuple [ M.get_name (| globals, "log_entry" |) ]
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |),
+        make_tuple [ M.get_name (| globals, locals_stack, "log_entry" |) ]
       |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition log0 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -203,9 +206,9 @@ Definition log0 : Value.t := M.run ltac:(M.monadic (
 
 Definition log1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -213,9 +216,9 @@ Definition log1 : Value.t := M.run ltac:(M.monadic (
 
 Definition log2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -223,9 +226,9 @@ Definition log2 : Value.t := M.run ltac:(M.monadic (
 
 Definition log3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
@@ -233,9 +236,9 @@ Definition log3 : Value.t := M.run ltac:(M.monadic (
 
 Definition log4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "log_n" |)
+      M.get_name (| globals, locals_stack, "log_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/memory.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/memory.v
index ca0b278..f7f9ed6 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/memory.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.memory".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition mstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a word to memory.
     This also expands the memory, if the memory is
@@ -61,9 +64,9 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -72,9 +75,9 @@ Definition mstore : Value.t -> Value.t -> M :=
       "value" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -85,17 +88,17 @@ Definition mstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "value" |)
+                    M.get_name (| globals, locals_stack, "value" |)
                   ],
                   make_dict []
                 |)
@@ -108,43 +111,44 @@ Definition mstore : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mstore8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a byte to memory.
     This also expands the memory, if the memory is
@@ -159,9 +163,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -169,9 +173,9 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -179,12 +183,12 @@ Definition mstore8 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 1
               ],
@@ -196,32 +200,32 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "normalized_bytes_value" ,
       M.call (|
-        M.get_name (| globals, "Bytes" |),
+        M.get_name (| globals, locals_stack, "Bytes" |),
         make_list [
           make_list [
             BinOp.bit_and (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 255
             |)
           ]
@@ -230,24 +234,25 @@ Definition mstore8 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "start_position" |);
-      M.get_name (| globals, "normalized_bytes_value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "start_position" |);
+      M.get_name (| globals, locals_stack, "normalized_bytes_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition mload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Load word from memory.
 
@@ -260,9 +265,9 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -270,12 +275,12 @@ Definition mload : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "start_position" |); M.call (|
-              M.get_name (| globals, "U256" |),
+            make_tuple [ M.get_name (| globals, locals_stack, "start_position" |); M.call (|
+              M.get_name (| globals, locals_stack, "U256" |),
               make_list [
                 Constant.int 32
               ],
@@ -287,36 +292,36 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_VERY_LOW" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "memory_read_bytes" |),
+            M.get_name (| globals, locals_stack, "memory_read_bytes" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-              M.get_name (| globals, "start_position" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+              M.get_name (| globals, locals_stack, "start_position" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -330,23 +335,24 @@ Definition mload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition msize : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Push the size of active memory in bytes onto the stack.
 
@@ -358,24 +364,24 @@ Definition msize : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "memory" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |)
             ],
             make_dict []
           |)
@@ -387,7 +393,7 @@ Definition msize : Value.t -> Value.t -> M :=
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/stack.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/stack.v
index 91f636b..6dcf61d 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/stack.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.stack".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_tangerine_whistle_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.tangerine_whistle.vm.memory" "buffer_read".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove item from stack.
 
@@ -57,31 +60,32 @@ Definition pop : Value.t -> Value.t -> M :=
 
     " in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_BASE" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_BASE" |)
     ],
     make_dict []
   |) in
     let _ := M.pass (| |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "num_bytes" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "num_bytes" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes a N-byte immediate onto the stack.
 
@@ -97,36 +101,36 @@ Definition push_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_push" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "code" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "code" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   BinOp.add (|
-                    M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+                    M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
                     Constant.int 1
                   |)
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
-                  M.get_name (| globals, "num_bytes" |)
+                  M.get_name (| globals, locals_stack, "num_bytes" |)
                 ],
                 make_dict []
               |)
@@ -138,26 +142,27 @@ Definition push_n : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_push" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_push" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       BinOp.add (|
     Constant.int 1,
-    M.get_name (| globals, "num_bytes" |)
+    M.get_name (| globals, locals_stack, "num_bytes" |)
   |)
     |) in
     M.pure Constant.None_)).
 
 Definition dup_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Duplicate the Nth stack item (from top of the stack) to the top of stack.
 
@@ -173,67 +178,68 @@ Definition dup_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "data_to_duplicate" ,
       M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           BinOp.sub (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+                M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
               ],
               make_dict []
             |),
             Constant.int 1
           |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |)
     |) in
     let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "stack" |), "push" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "data_to_duplicate" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "data_to_duplicate" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition swap_n : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "item_number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "item_number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Swap the top and the `item_number` element of the stack, where
     the top of the stack is position zero.
@@ -253,64 +259,64 @@ Definition swap_n : Value.t -> Value.t -> M :=
     " in
     let _ := M.pass (| |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_VERY_LOW" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_VERY_LOW" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "ensure" |),
+    M.get_name (| globals, locals_stack, "ensure" |),
     make_list [
       Compare.lt (|
-        M.get_name (| globals, "item_number" |),
+        M.get_name (| globals, locals_stack, "item_number" |),
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |)
       |);
-      M.get_name (| globals, "StackUnderflowError" |)
+      M.get_name (| globals, locals_stack, "StackUnderflowError" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |) ],
       make_tuple [ M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         BinOp.sub (|
           UnOp.sub (| Constant.int 1 |),
-          M.get_name (| globals, "item_number" |)
+          M.get_name (| globals, locals_stack, "item_number" |)
         |)
       |); M.get_subscript (|
-        M.get_field (| M.get_name (| globals, "evm" |), "stack" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |),
         UnOp.sub (| Constant.int 1 |)
       |) ]
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition push1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -318,9 +324,9 @@ Definition push1 : Value.t := M.run ltac:(M.monadic (
 
 Definition push2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -328,9 +334,9 @@ Definition push2 : Value.t := M.run ltac:(M.monadic (
 
 Definition push3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -338,9 +344,9 @@ Definition push3 : Value.t := M.run ltac:(M.monadic (
 
 Definition push4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -348,9 +354,9 @@ Definition push4 : Value.t := M.run ltac:(M.monadic (
 
 Definition push5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -358,9 +364,9 @@ Definition push5 : Value.t := M.run ltac:(M.monadic (
 
 Definition push6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -368,9 +374,9 @@ Definition push6 : Value.t := M.run ltac:(M.monadic (
 
 Definition push7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -378,9 +384,9 @@ Definition push7 : Value.t := M.run ltac:(M.monadic (
 
 Definition push8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -388,9 +394,9 @@ Definition push8 : Value.t := M.run ltac:(M.monadic (
 
 Definition push9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -398,9 +404,9 @@ Definition push9 : Value.t := M.run ltac:(M.monadic (
 
 Definition push10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -408,9 +414,9 @@ Definition push10 : Value.t := M.run ltac:(M.monadic (
 
 Definition push11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -418,9 +424,9 @@ Definition push11 : Value.t := M.run ltac:(M.monadic (
 
 Definition push12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -428,9 +434,9 @@ Definition push12 : Value.t := M.run ltac:(M.monadic (
 
 Definition push13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -438,9 +444,9 @@ Definition push13 : Value.t := M.run ltac:(M.monadic (
 
 Definition push14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -448,9 +454,9 @@ Definition push14 : Value.t := M.run ltac:(M.monadic (
 
 Definition push15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -458,9 +464,9 @@ Definition push15 : Value.t := M.run ltac:(M.monadic (
 
 Definition push16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -468,9 +474,9 @@ Definition push16 : Value.t := M.run ltac:(M.monadic (
 
 Definition push17 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -478,9 +484,9 @@ Definition push17 : Value.t := M.run ltac:(M.monadic (
 
 Definition push18 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -488,9 +494,9 @@ Definition push18 : Value.t := M.run ltac:(M.monadic (
 
 Definition push19 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -498,9 +504,9 @@ Definition push19 : Value.t := M.run ltac:(M.monadic (
 
 Definition push20 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -508,9 +514,9 @@ Definition push20 : Value.t := M.run ltac:(M.monadic (
 
 Definition push21 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -518,9 +524,9 @@ Definition push21 : Value.t := M.run ltac:(M.monadic (
 
 Definition push22 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -528,9 +534,9 @@ Definition push22 : Value.t := M.run ltac:(M.monadic (
 
 Definition push23 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -538,9 +544,9 @@ Definition push23 : Value.t := M.run ltac:(M.monadic (
 
 Definition push24 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -548,9 +554,9 @@ Definition push24 : Value.t := M.run ltac:(M.monadic (
 
 Definition push25 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -558,9 +564,9 @@ Definition push25 : Value.t := M.run ltac:(M.monadic (
 
 Definition push26 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -568,9 +574,9 @@ Definition push26 : Value.t := M.run ltac:(M.monadic (
 
 Definition push27 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -578,9 +584,9 @@ Definition push27 : Value.t := M.run ltac:(M.monadic (
 
 Definition push28 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -588,9 +594,9 @@ Definition push28 : Value.t := M.run ltac:(M.monadic (
 
 Definition push29 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -598,9 +604,9 @@ Definition push29 : Value.t := M.run ltac:(M.monadic (
 
 Definition push30 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -608,9 +614,9 @@ Definition push30 : Value.t := M.run ltac:(M.monadic (
 
 Definition push31 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -618,9 +624,9 @@ Definition push31 : Value.t := M.run ltac:(M.monadic (
 
 Definition push32 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "push_n" |)
+      M.get_name (| globals, locals_stack, "push_n" |)
     ],
     make_dict []
   |)
@@ -628,9 +634,9 @@ Definition push32 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -638,9 +644,9 @@ Definition dup1 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -648,9 +654,9 @@ Definition dup2 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -658,9 +664,9 @@ Definition dup3 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -668,9 +674,9 @@ Definition dup4 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -678,9 +684,9 @@ Definition dup5 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -688,9 +694,9 @@ Definition dup6 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -698,9 +704,9 @@ Definition dup7 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -708,9 +714,9 @@ Definition dup8 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -718,9 +724,9 @@ Definition dup9 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -728,9 +734,9 @@ Definition dup10 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -738,9 +744,9 @@ Definition dup11 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -748,9 +754,9 @@ Definition dup12 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -758,9 +764,9 @@ Definition dup13 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -768,9 +774,9 @@ Definition dup14 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -778,9 +784,9 @@ Definition dup15 : Value.t := M.run ltac:(M.monadic (
 
 Definition dup16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "dup_n" |)
+      M.get_name (| globals, locals_stack, "dup_n" |)
     ],
     make_dict []
   |)
@@ -788,9 +794,9 @@ Definition dup16 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap1 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -798,9 +804,9 @@ Definition swap1 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap2 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -808,9 +814,9 @@ Definition swap2 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap3 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -818,9 +824,9 @@ Definition swap3 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap4 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -828,9 +834,9 @@ Definition swap4 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap5 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -838,9 +844,9 @@ Definition swap5 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap6 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -848,9 +854,9 @@ Definition swap6 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap7 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -858,9 +864,9 @@ Definition swap7 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap8 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -868,9 +874,9 @@ Definition swap8 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap9 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -878,9 +884,9 @@ Definition swap9 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap10 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -888,9 +894,9 @@ Definition swap10 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap11 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -898,9 +904,9 @@ Definition swap11 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap12 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -908,9 +914,9 @@ Definition swap12 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap13 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -918,9 +924,9 @@ Definition swap13 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap14 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -928,9 +934,9 @@ Definition swap14 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap15 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
@@ -938,9 +944,9 @@ Definition swap15 : Value.t := M.run ltac:(M.monadic (
 
 Definition swap16 : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "partial" |),
+    M.get_name (| globals, locals_stack, "partial" |),
     make_list [
-      M.get_name (| globals, "swap_n" |)
+      M.get_name (| globals, locals_stack, "swap_n" |)
     ],
     make_dict []
   |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/storage.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/storage.v
index d1261c9..3679ce4 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/storage.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/storage.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.storage".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.storage".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -42,8 +44,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition sload : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Loads to the stack, the value corresponding to a certain key from the
     storage of the current account.
@@ -58,9 +61,9 @@ Definition sload : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -69,43 +72,44 @@ Definition sload : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_SLOAD" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_SLOAD" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
-      M.get_name (| globals, "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
+      M.get_name (| globals, locals_stack, "value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition sstore : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Stores a value at a certain key in the current context's storage.
 
@@ -119,9 +123,9 @@ Definition sstore : Value.t -> Value.t -> M :=
       "key" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_name (| globals, "pop" |),
+          M.get_name (| globals, locals_stack, "pop" |),
           make_list [
-            M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
           ],
           make_dict []
         |), "to_be_bytes32" |),
@@ -132,9 +136,9 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "new_value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -142,11 +146,11 @@ Definition sstore : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "current_value" ,
       M.call (|
-        M.get_name (| globals, "get_storage" |),
+        M.get_name (| globals, locals_stack, "get_storage" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-          M.get_name (| globals, "key" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+          M.get_name (| globals, locals_stack, "key" |)
         ],
         make_dict []
       |)
@@ -156,12 +160,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -170,14 +174,14 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_SET" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_SET" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "gas_cost" ,
-          M.get_name (| globals, "GAS_STORAGE_UPDATE" |)
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_UPDATE" |)
         |) in
         M.pure Constant.None_
       )) |) in
@@ -186,12 +190,12 @@ Definition sstore : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.eq (|
-            M.get_name (| globals, "new_value" |),
+            M.get_name (| globals, locals_stack, "new_value" |),
             Constant.int 0
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "current_value" |),
+              M.get_name (| globals, locals_stack, "current_value" |),
               Constant.int 0
             |)
           ))
@@ -200,8 +204,8 @@ Definition sstore : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "GAS_STORAGE_CLEAR_REFUND" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "GAS_STORAGE_CLEAR_REFUND" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -209,26 +213,26 @@ Definition sstore : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_storage" |),
+    M.get_name (| globals, locals_stack, "set_storage" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "key" |);
-      M.get_name (| globals, "new_value" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "key" |);
+      M.get_name (| globals, locals_stack, "new_value" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/system.v b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/system.v
index a103f8e..541db61 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/system.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/instructions/system.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.instructions.system".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.instructions.system".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -88,8 +90,9 @@ Axiom ethereum_tangerine_whistle_vm_stack_imports_push :
   IsImported globals "ethereum.tangerine_whistle.vm.stack" "push".
 
 Definition create : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Creates a new account with associated code.
 
@@ -102,9 +105,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "endowment" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -112,9 +115,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -122,9 +125,9 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -132,23 +135,23 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_CREATE" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_CREATE" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
@@ -156,12 +159,12 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "create_message_gas" ,
       M.call (|
-        M.get_name (| globals, "max_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "max_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |)
@@ -171,28 +174,28 @@ Definition create : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_op (|
       BinOp.sub,
-      M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-      M.get_name (| globals, "create_message_gas" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+      M.get_name (| globals, locals_stack, "create_message_gas" |)
     |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_address" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "sender" ,
       M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "sender_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "sender_address" |)
         ],
         make_dict []
       |)
@@ -200,14 +203,14 @@ Definition create : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "contract_address" ,
       M.call (|
-        M.get_name (| globals, "compute_contract_address" |),
+        M.get_name (| globals, locals_stack, "compute_contract_address" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
           M.get_field (| M.call (|
-            M.get_name (| globals, "get_account" |),
+            M.get_name (| globals, locals_stack, "get_account" |),
             make_list [
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-              M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+              M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
             ],
             make_dict []
           |), "nonce" |)
@@ -220,15 +223,15 @@ Definition create : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.or (|
           Compare.lt (|
-            M.get_field (| M.get_name (| globals, "sender" |), "balance" |),
-            M.get_name (| globals, "endowment" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "balance" |),
+            M.get_name (| globals, locals_stack, "endowment" |)
           |),
           ltac:(M.monadic (
             BoolOp.or (|
               Compare.eq (|
-                M.get_field (| M.get_name (| globals, "sender" |), "nonce" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "sender" |), "nonce" |),
                 M.call (|
-                  M.get_name (| globals, "Uint" |),
+                  M.get_name (| globals, locals_stack, "Uint" |),
                   make_list [
                     BinOp.sub (|
                       BinOp.pow (|
@@ -244,10 +247,10 @@ Definition create : Value.t -> Value.t -> M :=
               ltac:(M.monadic (
                 Compare.gt (|
                   BinOp.add (|
-                    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+                    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
                     Constant.int 1
                   |),
-                  M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+                  M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
                 |)
               ))
             |)
@@ -256,11 +259,11 @@ Definition create : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -271,8 +274,8 @@ Definition create : Value.t -> Value.t -> M :=
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "create_message_gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "create_message_gas" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -281,29 +284,29 @@ Definition create : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             M.call (|
-              M.get_name (| globals, "account_has_code_or_nonce" |),
+              M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
               make_list [
-                M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-                M.get_name (| globals, "contract_address" |)
+                M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+                M.get_name (| globals, locals_stack, "contract_address" |)
               ],
               make_dict []
             |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -318,27 +321,27 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "call_data" ,
               M.call (|
-                M.get_name (| globals, "memory_read_bytes" |),
+                M.get_name (| globals, locals_stack, "memory_read_bytes" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-                  M.get_name (| globals, "memory_start_position" |);
-                  M.get_name (| globals, "memory_size" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+                  M.get_name (| globals, locals_stack, "memory_start_position" |);
+                  M.get_name (| globals, locals_stack, "memory_size" |)
                 ],
                 make_dict []
               |)
             |) in
             let _ := M.call (|
-    M.get_name (| globals, "increment_nonce" |),
+    M.get_name (| globals, locals_stack, "increment_nonce" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     ],
     make_dict []
   |) in
             let _ := M.assign_local (|
               "child_message" ,
               M.call (|
-                M.get_name (| globals, "Message" |),
+                M.get_name (| globals, locals_stack, "Message" |),
                 make_list [],
                 make_dict []
               |)
@@ -346,10 +349,10 @@ Definition create : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "child_evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "child_message" |);
-                  M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+                  M.get_name (| globals, locals_stack, "child_message" |);
+                  M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
                 ],
                 make_dict []
               |)
@@ -357,23 +360,23 @@ Definition create : Value.t -> Value.t -> M :=
             let _ :=
               (* if *)
               M.if_then_else (|
-                M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
               (* then *)
               ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -386,21 +389,21 @@ Definition create : Value.t -> Value.t -> M :=
               (* else *)
               )), ltac:(M.monadic (
                 let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
                 let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "child_evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |)
@@ -415,14 +418,15 @@ Definition create : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition return_ : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halts execution returning output data.
 
@@ -434,9 +438,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -444,9 +448,9 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -454,57 +458,58 @@ Definition return_ : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_start_position" |); M.get_name (| globals, "memory_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_start_position" |); M.get_name (| globals, locals_stack, "memory_size" |) ]
           ]
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_ZERO" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_name (| globals, locals_stack, "GAS_ZERO" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_start_position" |);
-          M.get_name (| globals, "memory_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_size" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition generic_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "gas"; "value"; "caller"; "to"; "code_address"; "should_transfer_value"; "memory_input_start_position"; "memory_input_size"; "memory_output_start_position"; "memory_output_size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Perform the core logic of the `CALL*` family of opcodes.
     " in
@@ -514,24 +519,24 @@ Definition generic_call : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.gt (|
           BinOp.add (|
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "depth" |),
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "depth" |),
             Constant.int 1
           |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_name (| globals, "gas" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_name (| globals, locals_stack, "gas" |)
         |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -551,11 +556,11 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "call_data" ,
       M.call (|
-        M.get_name (| globals, "memory_read_bytes" |),
+        M.get_name (| globals, locals_stack, "memory_read_bytes" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-          M.get_name (| globals, "memory_input_start_position" |);
-          M.get_name (| globals, "memory_input_size" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+          M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+          M.get_name (| globals, locals_stack, "memory_input_size" |)
         ],
         make_dict []
       |)
@@ -563,10 +568,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "code_address" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "code_address" |)
         ],
         make_dict []
       |), "code" |)
@@ -574,7 +579,7 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_message" ,
       M.call (|
-        M.get_name (| globals, "Message" |),
+        M.get_name (| globals, locals_stack, "Message" |),
         make_list [],
         make_dict []
       |)
@@ -582,10 +587,10 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "child_evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "child_message" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "env" |)
+          M.get_name (| globals, locals_stack, "child_message" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |)
         ],
         make_dict []
       |)
@@ -593,23 +598,23 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_error" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_error" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -622,19 +627,19 @@ Definition generic_call : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "incorporate_child_on_success" |),
+    M.get_name (| globals, locals_stack, "incorporate_child_on_success" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "child_evm" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "child_evm" |)
     ],
     make_dict []
   |) in
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 1
         ],
@@ -648,16 +653,16 @@ Definition generic_call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "actual_output_size" ,
       M.call (|
-        M.get_name (| globals, "min" |),
+        M.get_name (| globals, locals_stack, "min" |),
         make_list [
-          M.get_name (| globals, "memory_output_size" |);
+          M.get_name (| globals, locals_stack, "memory_output_size" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "len" |),
+                M.get_name (| globals, locals_stack, "len" |),
                 make_list [
-                  M.get_field (| M.get_name (| globals, "child_evm" |), "output" |)
+                  M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |)
                 ],
                 make_dict []
               |)
@@ -669,14 +674,14 @@ Definition generic_call : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "memory_write" |),
+    M.get_name (| globals, locals_stack, "memory_write" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
-      M.get_name (| globals, "memory_output_start_position" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
       M.slice (|
-        M.get_field (| M.get_name (| globals, "child_evm" |), "output" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "child_evm" |), "output" |),
         Constant.None_,
-        M.get_name (| globals, "actual_output_size" |),
+        M.get_name (| globals, locals_stack, "actual_output_size" |),
         Constant.None_
       |)
     ],
@@ -685,8 +690,9 @@ Definition generic_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -698,12 +704,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -714,12 +720,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "to" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -730,9 +736,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -740,9 +746,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -750,9 +756,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -760,9 +766,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -770,9 +776,9 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -780,12 +786,12 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -794,10 +800,10 @@ Definition call : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "_account_exists" ,
       M.call (|
-        M.get_name (| globals, "account_exists" |),
+        M.get_name (| globals, locals_stack, "account_exists" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "to" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "to" |)
         ],
         make_dict []
       |)
@@ -806,11 +812,11 @@ Definition call : Value.t -> Value.t -> M :=
       "create_gas_cost" ,
             (* if *)
       M.if_then_else (|
-        M.get_name (| globals, "_account_exists" |),
+        M.get_name (| globals, locals_stack, "_account_exists" |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -818,7 +824,7 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
+M.get_name (| globals, locals_stack, "GAS_NEW_ACCOUNT" |)
       )) |)
     |) in
     let _ := M.assign_local (|
@@ -826,13 +832,13 @@ M.get_name (| globals, "GAS_NEW_ACCOUNT" |)
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -840,61 +846,61 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
             BinOp.add (|
-              M.get_name (| globals, "GAS_CALL" |),
-              M.get_name (| globals, "create_gas_cost" |)
+              M.get_name (| globals, locals_stack, "GAS_CALL" |),
+              M.get_name (| globals, locals_stack, "create_gas_cost" |)
             |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -903,17 +909,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -924,26 +930,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "to" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "to" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -951,14 +957,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition callcode : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into this account with alternative account’s code.
 
@@ -970,12 +977,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -986,12 +993,12 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1002,9 +1009,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "value" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1012,9 +1019,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1022,9 +1029,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1032,9 +1039,9 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1042,26 +1049,26 @@ Definition callcode : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign_local (|
       "to" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1072,13 +1079,13 @@ Definition callcode : Value.t -> Value.t -> M :=
             (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
       ltac:(M.monadic (
 M.call (|
-          M.get_name (| globals, "Uint" |),
+          M.get_name (| globals, locals_stack, "Uint" |),
           make_list [
             Constant.int 0
           ],
@@ -1086,58 +1093,58 @@ M.call (|
         |)
       (* else *)
       )), ltac:(M.monadic (
-M.get_name (| globals, "GAS_CALL_VALUE" |)
+M.get_name (| globals, locals_stack, "GAS_CALL_VALUE" |)
       )) |)
     |) in
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
-          M.get_name (| globals, "value" |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "value" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
           BinOp.add (|
-            M.get_name (| globals, "GAS_CALL" |),
-            M.get_name (| globals, "transfer_gas_cost" |)
+            M.get_name (| globals, locals_stack, "GAS_CALL" |),
+            M.get_name (| globals, locals_stack, "transfer_gas_cost" |)
           |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.assign_local (|
       "sender_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1146,17 +1153,17 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "sender_balance" |),
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "sender_balance" |),
+          M.get_name (| globals, locals_stack, "value" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "push" |),
+    M.get_name (| globals, locals_stack, "push" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "evm" |), "stack" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1167,26 +1174,26 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
   |) in
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |),
-          M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |)
         |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_name (| globals, "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "to" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_name (| globals, locals_stack, "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "to" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool true;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
@@ -1194,14 +1201,15 @@ M.get_name (| globals, "GAS_CALL_VALUE" |)
       )) |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
 
 Definition selfdestruct : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Halt execution and register account for later deletion.
 
@@ -1213,12 +1221,12 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "beneficiary" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1228,16 +1236,16 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     |) in
     let _ := M.assign_local (|
       "gas_cost" ,
-      M.get_name (| globals, "GAS_SELF_DESTRUCT" |)
+      M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT" |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         UnOp.not (| M.call (|
-          M.get_name (| globals, "account_exists" |),
+          M.get_name (| globals, locals_stack, "account_exists" |),
           make_list [
-            M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-            M.get_name (| globals, "beneficiary" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+            M.get_name (| globals, locals_stack, "beneficiary" |)
           ],
           make_dict []
         |) |),
@@ -1246,7 +1254,7 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         let _ := M.assign_op_local (|
           BinOp.add,
           "gas_cost",
-          M.get_name (| globals, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
+          M.get_name (| globals, locals_stack, "GAS_SELF_DESTRUCT_NEW_ACCOUNT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1255,33 +1263,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.assign_local (|
       "originator" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |)
     |) in
     let _ := M.assign_local (|
       "refunded_accounts" ,
-      M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
     |) in
     let _ := M.assign_local (|
       "parent_evm" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "parent_evm" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "parent_evm" |)
     |) in
     let _ :=
       M.while (|
         Compare.is_not (|
-      M.get_name (| globals, "parent_evm" |),
+      M.get_name (| globals, locals_stack, "parent_evm" |),
       Constant.None_
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "refunded_accounts" |), "update" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "refunded_accounts" |), "update" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "parent_evm" |), "accounts_to_delete" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "accounts_to_delete" |)
     ],
     make_dict []
   |) in
           let _ := M.assign_local (|
             "parent_evm" ,
-            M.get_field (| M.get_field (| M.get_name (| globals, "parent_evm" |), "message" |), "parent_evm" |)
+            M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "parent_evm" |), "message" |), "parent_evm" |)
           |) in
           M.pure Constant.None_
         )),
@@ -1293,15 +1301,15 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.not_in (|
-          M.get_name (| globals, "originator" |),
-          M.get_name (| globals, "refunded_accounts" |)
+          M.get_name (| globals, locals_stack, "originator" |),
+          M.get_name (| globals, locals_stack, "refunded_accounts" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_op (|
           BinOp.add,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |),
-          M.get_name (| globals, "REFUND_SELF_DESTRUCT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |),
+          M.get_name (| globals, locals_stack, "REFUND_SELF_DESTRUCT" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -1309,20 +1317,20 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "gas_cost" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "gas_cost" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "beneficiary_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "beneficiary" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "beneficiary" |)
         ],
         make_dict []
       |), "balance" |)
@@ -1330,33 +1338,33 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "originator_balance" ,
       M.get_field (| M.call (|
-        M.get_name (| globals, "get_account" |),
+        M.get_name (| globals, locals_stack, "get_account" |),
         make_list [
-          M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-          M.get_name (| globals, "originator" |)
+          M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+          M.get_name (| globals, locals_stack, "originator" |)
         ],
         make_dict []
       |), "balance" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "beneficiary" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "beneficiary" |);
       BinOp.add (|
-        M.get_name (| globals, "beneficiary_balance" |),
-        M.get_name (| globals, "originator_balance" |)
+        M.get_name (| globals, locals_stack, "beneficiary_balance" |),
+        M.get_name (| globals, locals_stack, "originator_balance" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "set_account_balance" |),
+    M.get_name (| globals, locals_stack, "set_account_balance" |),
     make_list [
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "env" |), "state" |);
-      M.get_name (| globals, "originator" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "env" |), "state" |);
+      M.get_name (| globals, locals_stack, "originator" |);
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           Constant.int 0
         ],
@@ -1366,22 +1374,23 @@ Definition selfdestruct : Value.t -> Value.t -> M :=
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |), "add" |),
+    M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |), "add" |),
     make_list [
-      M.get_name (| globals, "originator" |)
+      M.get_name (| globals, locals_stack, "originator" |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "running" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "running" |),
       Constant.bool false
     |) in
     let _ := M.pass (| |) in
     M.pure Constant.None_)).
 
 Definition delegatecall : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Message-call into an account.
 
@@ -1393,12 +1402,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "gas" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1409,12 +1418,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "code_address" ,
       M.call (|
-        M.get_name (| globals, "to_address" |),
+        M.get_name (| globals, locals_stack, "to_address" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "pop" |),
+            M.get_name (| globals, locals_stack, "pop" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
             ],
             make_dict []
           |)
@@ -1425,9 +1434,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1435,9 +1444,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_input_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1445,9 +1454,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_start_position" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1455,9 +1464,9 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "memory_output_size" ,
       M.call (|
-        M.get_name (| globals, "pop" |),
+        M.get_name (| globals, locals_stack, "pop" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "stack" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "stack" |)
         ],
         make_dict []
       |)
@@ -1465,12 +1474,12 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "extend_memory" ,
       M.call (|
-        M.get_name (| globals, "calculate_gas_extend_memory" |),
+        M.get_name (| globals, locals_stack, "calculate_gas_extend_memory" |),
         make_list [
-          M.get_field (| M.get_name (| globals, "evm" |), "memory" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |);
           make_list [
-            make_tuple [ M.get_name (| globals, "memory_input_start_position" |); M.get_name (| globals, "memory_input_size" |) ];
-            make_tuple [ M.get_name (| globals, "memory_output_start_position" |); M.get_name (| globals, "memory_output_size" |) ]
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_input_start_position" |); M.get_name (| globals, locals_stack, "memory_input_size" |) ];
+            make_tuple [ M.get_name (| globals, locals_stack, "memory_output_start_position" |); M.get_name (| globals, locals_stack, "memory_output_size" |) ]
           ]
         ],
         make_dict []
@@ -1479,68 +1488,68 @@ Definition delegatecall : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_call_gas" ,
       M.call (|
-        M.get_name (| globals, "calculate_message_call_gas" |),
+        M.get_name (| globals, locals_stack, "calculate_message_call_gas" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
-          M.get_name (| globals, "gas" |);
+          M.get_name (| globals, locals_stack, "gas" |);
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
             ],
             make_dict []
           |);
-          M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |);
-          M.get_name (| globals, "GAS_CALL" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |);
+          M.get_name (| globals, locals_stack, "GAS_CALL" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_field (| M.get_name (| globals, "message_call_gas" |), "cost" |),
-        M.get_field (| M.get_name (| globals, "extend_memory" |), "cost" |)
+        M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "cost" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "cost" |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "memory" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "memory" |),
       BinOp.mult (|
     Constant.bytes "00",
-    M.get_field (| M.get_name (| globals, "extend_memory" |), "expand_by" |)
+    M.get_field (| M.get_name (| globals, locals_stack, "extend_memory" |), "expand_by" |)
   |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "generic_call" |),
+    M.get_name (| globals, locals_stack, "generic_call" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_field (| M.get_name (| globals, "message_call_gas" |), "stipend" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "value" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "caller" |);
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "current_target" |);
-      M.get_name (| globals, "code_address" |);
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message_call_gas" |), "stipend" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "value" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "caller" |);
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "current_target" |);
+      M.get_name (| globals, locals_stack, "code_address" |);
       Constant.bool false;
-      M.get_name (| globals, "memory_input_start_position" |);
-      M.get_name (| globals, "memory_input_size" |);
-      M.get_name (| globals, "memory_output_start_position" |);
-      M.get_name (| globals, "memory_output_size" |)
+      M.get_name (| globals, locals_stack, "memory_input_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_input_size" |);
+      M.get_name (| globals, locals_stack, "memory_output_start_position" |);
+      M.get_name (| globals, locals_stack, "memory_output_size" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_op (|
       BinOp.add,
-      M.get_field (| M.get_name (| globals, "evm" |), "pc" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "pc" |),
       Constant.int 1
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/interpreter.v b/CoqOfPython/ethereum/tangerine_whistle/vm/interpreter.v
index df0b3aa..2179c16 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/interpreter.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/interpreter.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.interpreter".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.interpreter".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -109,7 +111,7 @@ Axiom ethereum_tangerine_whistle_vm_runtime_imports_get_valid_jump_destinations
 
 Definition STACK_DEPTH_LIMIT : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "U256" |),
+    M.get_name (| globals, locals_stack, "U256" |),
     make_list [
       Constant.int 1024
     ],
@@ -128,8 +130,9 @@ Definition MessageCallOutput : Value.t :=
     ].
 
 Definition process_message_call : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     If `message.current` is empty then it creates a smart contract
     else it executes a call from the `message.caller` to the `message.target`.
@@ -151,9 +154,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_field (| M.get_name (| globals, "message" |), "target" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "target" |),
           M.call (|
-            M.get_name (| globals, "Bytes0" |),
+            M.get_name (| globals, locals_stack, "Bytes0" |),
             make_list [
               Constant.bytes ""
             ],
@@ -165,10 +168,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "is_collision" ,
           M.call (|
-            M.get_name (| globals, "account_has_code_or_nonce" |),
+            M.get_name (| globals, locals_stack, "account_has_code_or_nonce" |),
             make_list [
-              M.get_field (| M.get_name (| globals, "env" |), "state" |);
-              M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+              M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
             ],
             make_dict []
           |)
@@ -176,39 +179,39 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ :=
           (* if *)
           M.if_then_else (|
-            M.get_name (| globals, "is_collision" |),
+            M.get_name (| globals, locals_stack, "is_collision" |),
           (* then *)
           ltac:(M.monadic (
             let _ := M.return_ (|
               M.call (|
-                M.get_name (| globals, "MessageCallOutput" |),
+                M.get_name (| globals, locals_stack, "MessageCallOutput" |),
                 make_list [
                   M.call (|
-                    M.get_name (| globals, "Uint" |),
+                    M.get_name (| globals, locals_stack, "Uint" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "U256" |),
+                    M.get_name (| globals, locals_stack, "U256" |),
                     make_list [
                       Constant.int 0
                     ],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "tuple" |),
+                    M.get_name (| globals, locals_stack, "tuple" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "set" |),
+                    M.get_name (| globals, locals_stack, "set" |),
                     make_list [],
                     make_dict []
                   |);
                   M.call (|
-                    M.get_name (| globals, "AddressCollision" |),
+                    M.get_name (| globals, locals_stack, "AddressCollision" |),
                     make_list [],
                     make_dict []
                   |)
@@ -222,10 +225,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
             let _ := M.assign_local (|
               "evm" ,
               M.call (|
-                M.get_name (| globals, "process_create_message" |),
+                M.get_name (| globals, locals_stack, "process_create_message" |),
                 make_list [
-                  M.get_name (| globals, "message" |);
-                  M.get_name (| globals, "env" |)
+                  M.get_name (| globals, locals_stack, "message" |);
+                  M.get_name (| globals, locals_stack, "env" |)
                 ],
                 make_dict []
               |)
@@ -238,10 +241,10 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "evm" ,
           M.call (|
-            M.get_name (| globals, "process_message" |),
+            M.get_name (| globals, locals_stack, "process_message" |),
             make_list [
-              M.get_name (| globals, "message" |);
-              M.get_name (| globals, "env" |)
+              M.get_name (| globals, locals_stack, "message" |);
+              M.get_name (| globals, locals_stack, "env" |)
             ],
             make_dict []
           |)
@@ -251,14 +254,14 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
 (* At stmt: unsupported node type: AnnAssign *)
         let _ := M.assign_local (|
           "accounts_to_delete" ,
           M.call (|
-            M.get_name (| globals, "set" |),
+            M.get_name (| globals, locals_stack, "set" |),
             make_list [],
             make_dict []
           |)
@@ -266,7 +269,7 @@ Definition process_message_call : Value.t -> Value.t -> M :=
         let _ := M.assign_local (|
           "refund_counter" ,
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
@@ -278,44 +281,44 @@ Definition process_message_call : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         let _ := M.assign_local (|
           "logs" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "logs" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "logs" |)
         |) in
         let _ := M.assign_local (|
           "accounts_to_delete" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "accounts_to_delete" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "accounts_to_delete" |)
         |) in
         let _ := M.assign_local (|
           "refund_counter" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "refund_counter" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "refund_counter" |)
         |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.assign_local (|
       "tx_end" ,
       M.call (|
-        M.get_name (| globals, "TransactionEnd" |),
+        M.get_name (| globals, locals_stack, "TransactionEnd" |),
         make_list [
           BinOp.sub (|
-            M.get_field (| M.get_name (| globals, "message" |), "gas" |),
-            M.get_field (| M.get_name (| globals, "evm" |), "gas_left" |)
+            M.get_field (| M.get_name (| globals, locals_stack, "message" |), "gas" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "gas_left" |)
           |);
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |);
-          M.get_field (| M.get_name (| globals, "evm" |), "error" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |);
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "evm_trace" |),
+    M.get_name (| globals, locals_stack, "evm_trace" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "tx_end" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "tx_end" |)
     ],
     make_dict []
   |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "MessageCallOutput" |),
+        M.get_name (| globals, locals_stack, "MessageCallOutput" |),
         make_list [],
         make_dict []
       |)
@@ -323,8 +326,9 @@ Definition process_message_call : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition process_create_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -341,27 +345,27 @@ Definition process_create_message : Value.t -> Value.t -> M :=
         Items containing execution specific objects.
     " in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "destroy_storage" |),
+    M.get_name (| globals, locals_stack, "destroy_storage" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "process_message" |),
+        M.get_name (| globals, locals_stack, "process_message" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -369,24 +373,24 @@ Definition process_create_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        UnOp.not (| M.get_field (| M.get_name (| globals, "evm" |), "error" |) |),
+        UnOp.not (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |) |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.assign_local (|
           "contract_code" ,
-          M.get_field (| M.get_name (| globals, "evm" |), "output" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |)
         |) in
         let _ := M.assign_local (|
           "contract_code_gas" ,
           BinOp.mult (|
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
-                M.get_name (| globals, "contract_code" |)
+                M.get_name (| globals, locals_stack, "contract_code" |)
               ],
               make_dict []
             |),
-            M.get_name (| globals, "GAS_CODE_DEPOSIT" |)
+            M.get_name (| globals, locals_stack, "GAS_CODE_DEPOSIT" |)
           |)
         |) in
 (* At stmt: unsupported node type: Try *)
@@ -394,22 +398,23 @@ Definition process_create_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition process_message : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes a call to create a smart contract.
 
@@ -429,13 +434,13 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.gt (|
-          M.get_field (| M.get_name (| globals, "message" |), "depth" |),
-          M.get_name (| globals, "STACK_DEPTH_LIMIT" |)
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "depth" |),
+          M.get_name (| globals, locals_stack, "STACK_DEPTH_LIMIT" |)
         |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.raise (| Some (M.call (|
-          M.get_name (| globals, "StackDepthLimitError" |),
+          M.get_name (| globals, locals_stack, "StackDepthLimitError" |),
           make_list [
             Constant.str "Stack depth limit reached"
           ],
@@ -447,17 +452,17 @@ Definition process_message : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.call (|
-    M.get_name (| globals, "begin_transaction" |),
+    M.get_name (| globals, locals_stack, "begin_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
     let _ := M.call (|
-    M.get_name (| globals, "touch_account" |),
+    M.get_name (| globals, locals_stack, "touch_account" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |)
     ],
     make_dict []
   |) in
@@ -465,10 +470,10 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         BoolOp.and (|
-          M.get_field (| M.get_name (| globals, "message" |), "should_transfer_value" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "message" |), "should_transfer_value" |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_field (| M.get_name (| globals, "message" |), "value" |),
+              M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |),
               Constant.int 0
             |)
           ))
@@ -476,12 +481,12 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "move_ether" |),
+    M.get_name (| globals, locals_stack, "move_ether" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |);
-      M.get_field (| M.get_name (| globals, "message" |), "caller" |);
-      M.get_field (| M.get_name (| globals, "message" |), "current_target" |);
-      M.get_field (| M.get_name (| globals, "message" |), "value" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "caller" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "current_target" |);
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "value" |)
     ],
     make_dict []
   |) in
@@ -493,10 +498,10 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "execute_code" |),
+        M.get_name (| globals, locals_stack, "execute_code" |),
         make_list [
-          M.get_name (| globals, "message" |);
-          M.get_name (| globals, "env" |)
+          M.get_name (| globals, locals_stack, "message" |);
+          M.get_name (| globals, locals_stack, "env" |)
         ],
         make_dict []
       |)
@@ -504,13 +509,13 @@ Definition process_message : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_field (| M.get_name (| globals, "evm" |), "error" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "error" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "rollback_transaction" |),
+    M.get_name (| globals, locals_stack, "rollback_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
@@ -518,22 +523,23 @@ Definition process_message : Value.t -> Value.t -> M :=
       (* else *)
       )), ltac:(M.monadic (
         let _ := M.call (|
-    M.get_name (| globals, "commit_transaction" |),
+    M.get_name (| globals, locals_stack, "commit_transaction" |),
     make_list [
-      M.get_field (| M.get_name (| globals, "env" |), "state" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "env" |), "state" |)
     ],
     make_dict []
   |) in
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
 
 Definition execute_code : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "message"; "env" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "message"; "env" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Executes bytecode present in the `message`.
 
@@ -551,14 +557,14 @@ Definition execute_code : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "code" ,
-      M.get_field (| M.get_name (| globals, "message" |), "code" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "message" |), "code" |)
     |) in
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "get_valid_jump_destinations" |),
+        M.get_name (| globals, locals_stack, "get_valid_jump_destinations" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -566,13 +572,13 @@ Definition execute_code : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "evm" ,
       M.call (|
-        M.get_name (| globals, "Evm" |),
+        M.get_name (| globals, locals_stack, "Evm" |),
         make_list [],
         make_dict []
       |)
     |) in
 (* At stmt: unsupported node type: Try *)
     let _ := M.return_ (|
-      M.get_name (| globals, "evm" |)
+      M.get_name (| globals, locals_stack, "evm" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/memory.v b/CoqOfPython/ethereum/tangerine_whistle/vm/memory.v
index e8d40e2..d93ced6 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/memory.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/memory.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.memory".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.memory".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition memory_write : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes to memory.
 
@@ -44,33 +47,34 @@ Definition memory_write : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "value" |)
+              M.get_name (| globals, locals_stack, "value" |)
             ],
             make_dict []
           |)
         |),
         Constant.None_
       |),
-      M.get_name (| globals, "value" |)
+      M.get_name (| globals, locals_stack, "value" |)
     |) in
     M.pure Constant.None_)).
 
 Definition memory_read_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "memory"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "memory"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from memory.
 
@@ -90,20 +94,20 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.slice (|
-        M.get_name (| globals, "memory" |),
-        M.get_name (| globals, "start_position" |),
+        M.get_name (| globals, locals_stack, "memory" |),
+        M.get_name (| globals, locals_stack, "start_position" |),
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "start_position" |)
+              M.get_name (| globals, locals_stack, "start_position" |)
             ],
             make_dict []
           |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
-              M.get_name (| globals, "size" |)
+              M.get_name (| globals, locals_stack, "size" |)
             ],
             make_dict []
           |)
@@ -114,8 +118,9 @@ Definition memory_read_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition buffer_read : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "buffer"; "start_position"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "buffer"; "start_position"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Read bytes from a buffer. Padding with zeros if necessary.
 
@@ -135,30 +140,30 @@ Definition buffer_read : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "right_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "right_pad_zero_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "buffer" |),
-            M.get_name (| globals, "start_position" |),
+            M.get_name (| globals, locals_stack, "buffer" |),
+            M.get_name (| globals, locals_stack, "start_position" |),
             BinOp.add (|
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "start_position" |)
+                  M.get_name (| globals, locals_stack, "start_position" |)
                 ],
                 make_dict []
               |),
               M.call (|
-                M.get_name (| globals, "Uint" |),
+                M.get_name (| globals, locals_stack, "Uint" |),
                 make_list [
-                  M.get_name (| globals, "size" |)
+                  M.get_name (| globals, locals_stack, "size" |)
                 ],
                 make_dict []
               |)
             |),
             Constant.None_
           |);
-          M.get_name (| globals, "size" |)
+          M.get_name (| globals, locals_stack, "size" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/__init__.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/__init__.v
index 8931f02..c1cb983 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/__init__.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.__init__".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,7 +29,7 @@ Definition __all__ : Value.t := M.run ltac:(M.monadic (
 
 Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x01"
     ],
@@ -37,7 +39,7 @@ Definition ECRECOVER_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x02"
     ],
@@ -47,7 +49,7 @@ Definition SHA256_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x03"
     ],
@@ -57,7 +59,7 @@ Definition RIPEMD160_ADDRESS : Value.t := M.run ltac:(M.monadic (
 
 Definition IDENTITY_ADDRESS : Value.t := M.run ltac:(M.monadic (
   M.call (|
-    M.get_name (| globals, "hex_to_address" |),
+    M.get_name (| globals, locals_stack, "hex_to_address" |),
     make_list [
       Constant.str "0x04"
     ],
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ecrecover.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ecrecover.v
index 1d6afbb..3ffd572 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ecrecover.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ecrecover.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.ecrecover".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.ecrecover".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -45,8 +47,9 @@ Axiom ethereum_tangerine_whistle_vm_memory_imports_buffer_read :
   IsImported globals "ethereum.tangerine_whistle.vm.memory" "buffer_read".
 
 Definition ecrecover : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Decrypts the address using elliptic curve DSA recovery mechanism and writes
     the address to output.
@@ -58,31 +61,31 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
-      M.get_name (| globals, "GAS_ECRECOVER" |)
+      M.get_name (| globals, locals_stack, "evm" |);
+      M.get_name (| globals, locals_stack, "GAS_ECRECOVER" |)
     ],
     make_dict []
   |) in
     let _ := M.assign_local (|
       "message_hash_bytes" ,
       M.call (|
-        M.get_name (| globals, "buffer_read" |),
+        M.get_name (| globals, locals_stack, "buffer_read" |),
         make_list [
-          M.get_name (| globals, "data" |);
+          M.get_name (| globals, locals_stack, "data" |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 0
             ],
             make_dict []
           |);
           M.call (|
-            M.get_name (| globals, "U256" |),
+            M.get_name (| globals, locals_stack, "U256" |),
             make_list [
               Constant.int 32
             ],
@@ -95,9 +98,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "message_hash" ,
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
-          M.get_name (| globals, "message_hash_bytes" |)
+          M.get_name (| globals, locals_stack, "message_hash_bytes" |)
         ],
         make_dict []
       |)
@@ -105,21 +108,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "v" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -135,21 +138,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "r" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 64
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -165,21 +168,21 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "s" ,
       M.call (|
-        M.get_field (| M.get_name (| globals, "U256" |), "from_be_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U256" |), "from_be_bytes" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "buffer_read" |),
+            M.get_name (| globals, locals_stack, "buffer_read" |),
             make_list [
-              M.get_name (| globals, "data" |);
+              M.get_name (| globals, locals_stack, "data" |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 96
                 ],
                 make_dict []
               |);
               M.call (|
-                M.get_name (| globals, "U256" |),
+                M.get_name (| globals, locals_stack, "U256" |),
                 make_list [
                   Constant.int 32
                 ],
@@ -197,12 +200,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       M.if_then_else (|
         BoolOp.and (|
           Compare.not_eq (|
-            M.get_name (| globals, "v" |),
+            M.get_name (| globals, locals_stack, "v" |),
             Constant.int 27
           |),
           ltac:(M.monadic (
             Compare.not_eq (|
-              M.get_name (| globals, "v" |),
+              M.get_name (| globals, locals_stack, "v" |),
               Constant.int 28
             |)
           ))
@@ -223,12 +226,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "r" |)
+            M.get_name (| globals, locals_stack, "r" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "r" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "r" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -248,12 +251,12 @@ Definition ecrecover : Value.t -> Value.t -> M :=
         BoolOp.or (|
           Compare.gt_e (|
             Constant.int 0,
-            M.get_name (| globals, "s" |)
+            M.get_name (| globals, locals_stack, "s" |)
           |),
           ltac:(M.monadic (
             Compare.gt_e (|
-              M.get_name (| globals, "s" |),
-              M.get_name (| globals, "SECP256K1N" |)
+              M.get_name (| globals, locals_stack, "s" |),
+              M.get_name (| globals, locals_stack, "SECP256K1N" |)
             |)
           ))
         |),
@@ -272,9 +275,9 @@ Definition ecrecover : Value.t -> Value.t -> M :=
       "address" ,
       M.slice (|
         M.call (|
-          M.get_name (| globals, "keccak256" |),
+          M.get_name (| globals, locals_stack, "keccak256" |),
           make_list [
-            M.get_name (| globals, "public_key" |)
+            M.get_name (| globals, locals_stack, "public_key" |)
           ],
           make_dict []
         |),
@@ -286,16 +289,16 @@ Definition ecrecover : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_address" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "address" |);
+          M.get_name (| globals, locals_stack, "address" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_address" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_address" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/identity.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/identity.v
index 9226b27..667269e 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/identity.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/identity.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.identity".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.identity".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -34,8 +36,9 @@ Axiom ethereum_tangerine_whistle_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.tangerine_whistle.vm.gas" "charge_gas".
 
 Definition identity : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the message data to output.
 
@@ -46,21 +49,21 @@ Definition identity : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -74,21 +77,21 @@ Definition identity : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_IDENTITY" |),
+        M.get_name (| globals, locals_stack, "GAS_IDENTITY" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_IDENTITY_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_IDENTITY_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "data" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "data" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/mapping.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/mapping.v
index 450b048..f9cde09 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/mapping.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/mapping.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.mapping".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.mapping".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ripemd160.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ripemd160.v
index 52fd66f..b907551 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ripemd160.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/ripemd160.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.ripemd160".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.ripemd160".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -39,8 +41,9 @@ Axiom ethereum_tangerine_whistle_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.tangerine_whistle.vm.gas" "charge_gas".
 
 Definition ripemd160 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the ripemd160 hash to output.
 
@@ -51,21 +54,21 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -79,14 +82,14 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_RIPEMD160" |),
+        M.get_name (| globals, locals_stack, "GAS_RIPEMD160" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_RIPEMD160_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_RIPEMD160_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
@@ -96,10 +99,10 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
       "hash_bytes" ,
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "new" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "new" |),
           make_list [
             Constant.str "ripemd160";
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
@@ -110,16 +113,16 @@ Definition ripemd160 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "padded_hash" ,
       M.call (|
-        M.get_name (| globals, "left_pad_zero_bytes" |),
+        M.get_name (| globals, locals_stack, "left_pad_zero_bytes" |),
         make_list [
-          M.get_name (| globals, "hash_bytes" |);
+          M.get_name (| globals, locals_stack, "hash_bytes" |);
           Constant.int 32
         ],
         make_dict []
       |)
     |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
-      M.get_name (| globals, "padded_hash" |)
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
+      M.get_name (| globals, locals_stack, "padded_hash" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/sha256.v b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/sha256.v
index 5144a3e..973a752 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/sha256.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/precompiled_contracts/sha256.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.precompiled_contracts.sha256".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.precompiled_contracts.sha256".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -36,8 +38,9 @@ Axiom ethereum_tangerine_whistle_vm_gas_imports_charge_gas :
   IsImported globals "ethereum.tangerine_whistle.vm.gas" "charge_gas".
 
 Definition sha256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Writes the sha256 hash to output.
 
@@ -48,21 +51,21 @@ Definition sha256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.assign_local (|
       "data" ,
-      M.get_field (| M.get_field (| M.get_name (| globals, "evm" |), "message" |), "data" |)
+      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "message" |), "data" |)
     |) in
     let _ := M.assign_local (|
       "word_count" ,
       BinOp.floor_div (|
         M.call (|
-          M.get_name (| globals, "ceil32" |),
+          M.get_name (| globals, locals_stack, "ceil32" |),
           make_list [
             M.call (|
-              M.get_name (| globals, "Uint" |),
+              M.get_name (| globals, locals_stack, "Uint" |),
               make_list [
                 M.call (|
-                  M.get_name (| globals, "len" |),
+                  M.get_name (| globals, locals_stack, "len" |),
                   make_list [
-                    M.get_name (| globals, "data" |)
+                    M.get_name (| globals, locals_stack, "data" |)
                   ],
                   make_dict []
                 |)
@@ -76,26 +79,26 @@ Definition sha256 : Value.t -> Value.t -> M :=
       |)
     |) in
     let _ := M.call (|
-    M.get_name (| globals, "charge_gas" |),
+    M.get_name (| globals, locals_stack, "charge_gas" |),
     make_list [
-      M.get_name (| globals, "evm" |);
+      M.get_name (| globals, locals_stack, "evm" |);
       BinOp.add (|
-        M.get_name (| globals, "GAS_SHA256" |),
+        M.get_name (| globals, locals_stack, "GAS_SHA256" |),
         BinOp.mult (|
-          M.get_name (| globals, "GAS_SHA256_WORD" |),
-          M.get_name (| globals, "word_count" |)
+          M.get_name (| globals, locals_stack, "GAS_SHA256_WORD" |),
+          M.get_name (| globals, locals_stack, "word_count" |)
         |)
       |)
     ],
     make_dict []
   |) in
     let _ := M.assign (|
-      M.get_field (| M.get_name (| globals, "evm" |), "output" |),
+      M.get_field (| M.get_name (| globals, locals_stack, "evm" |), "output" |),
       M.call (|
         M.get_field (| M.call (|
-          M.get_field (| M.get_name (| globals, "hashlib" |), "sha256" |),
+          M.get_field (| M.get_name (| globals, locals_stack, "hashlib" |), "sha256" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |), "digest" |),
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/runtime.v b/CoqOfPython/ethereum/tangerine_whistle/vm/runtime.v
index fc5eb03..b22af1f 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/runtime.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/runtime.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.runtime".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.runtime".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -27,8 +29,9 @@ Axiom ethereum_tangerine_whistle_vm_instructions_imports_Ops :
   IsImported globals "ethereum.tangerine_whistle.vm.instructions" "Ops".
 
 Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "code" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "code" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Analyze the evm code to obtain the set of valid jump destinations.
 
@@ -53,7 +56,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "valid_jump_destinations" ,
       M.call (|
-        M.get_name (| globals, "set" |),
+        M.get_name (| globals, locals_stack, "set" |),
         make_list [],
         make_dict []
       |)
@@ -61,7 +64,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "pc" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 0
         ],
@@ -71,11 +74,11 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
     let _ :=
       M.while (|
         Compare.lt (|
-      M.get_name (| globals, "pc" |),
+      M.get_name (| globals, locals_stack, "pc" |),
       M.call (|
-        M.get_name (| globals, "len" |),
+        M.get_name (| globals, locals_stack, "len" |),
         make_list [
-          M.get_name (| globals, "code" |)
+          M.get_name (| globals, locals_stack, "code" |)
         ],
         make_dict []
       |)
@@ -86,15 +89,15 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
             (* if *)
             M.if_then_else (|
               Compare.eq (|
-                M.get_name (| globals, "current_opcode" |),
-                M.get_field (| M.get_name (| globals, "Ops" |), "JUMPDEST" |)
+                M.get_name (| globals, locals_stack, "current_opcode" |),
+                M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "JUMPDEST" |)
               |),
             (* then *)
             ltac:(M.monadic (
               let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "valid_jump_destinations" |), "add" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "valid_jump_destinations" |), "add" |),
     make_list [
-      M.get_name (| globals, "pc" |)
+      M.get_name (| globals, locals_stack, "pc" |)
     ],
     make_dict []
   |) in
@@ -106,13 +109,13 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                 M.if_then_else (|
                   BoolOp.and (|
                     Compare.lt_e (|
-                      M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |),
-                      M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |)
+                      M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |),
+                      M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |)
                     |),
                     ltac:(M.monadic (
                       Compare.lt_e (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH32" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH32" |), "value" |)
                       |)
                     ))
                   |),
@@ -122,8 +125,8 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                     "push_data_size" ,
                     BinOp.add (|
                       BinOp.sub (|
-                        M.get_field (| M.get_name (| globals, "current_opcode" |), "value" |),
-                        M.get_field (| M.get_field (| M.get_name (| globals, "Ops" |), "PUSH1" |), "value" |)
+                        M.get_field (| M.get_name (| globals, locals_stack, "current_opcode" |), "value" |),
+                        M.get_field (| M.get_field (| M.get_name (| globals, locals_stack, "Ops" |), "PUSH1" |), "value" |)
                       |),
                       Constant.int 1
                     |)
@@ -131,7 +134,7 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
                   let _ := M.assign_op_local (|
                     BinOp.add,
                     "pc",
-                    M.get_name (| globals, "push_data_size" |)
+                    M.get_name (| globals, locals_stack, "push_data_size" |)
                   |) in
                   M.pure Constant.None_
                 (* else *)
@@ -152,6 +155,6 @@ Definition get_valid_jump_destinations : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "valid_jump_destinations" |)
+      M.get_name (| globals, locals_stack, "valid_jump_destinations" |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/tangerine_whistle/vm/stack.v b/CoqOfPython/ethereum/tangerine_whistle/vm/stack.v
index 6311bf2..2a61b4d 100644
--- a/CoqOfPython/ethereum/tangerine_whistle/vm/stack.v
+++ b/CoqOfPython/ethereum/tangerine_whistle/vm/stack.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.tangerine_whistle.vm.stack".
+Definition globals : Globals.t := "ethereum.tangerine_whistle.vm.stack".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -29,8 +31,9 @@ Axiom ethereum_tangerine_whistle_vm_exceptions_imports_StackUnderflowError :
   IsImported globals "ethereum.tangerine_whistle.vm.exceptions" "StackUnderflowError".
 
 Definition pop : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pops the top item off of `stack`.
 
@@ -50,9 +53,9 @@ Definition pop : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -60,7 +63,7 @@ Definition pop : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackUnderflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackUnderflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -68,7 +71,7 @@ Definition pop : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "pop" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "pop" |),
         make_list [],
         make_dict []
       |)
@@ -76,8 +79,9 @@ Definition pop : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition push : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "stack"; "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "stack"; "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Pushes `value` onto `stack`.
 
@@ -95,9 +99,9 @@ Definition push : Value.t -> Value.t -> M :=
       M.if_then_else (|
         Compare.eq (|
           M.call (|
-            M.get_name (| globals, "len" |),
+            M.get_name (| globals, locals_stack, "len" |),
             make_list [
-              M.get_name (| globals, "stack" |)
+              M.get_name (| globals, locals_stack, "stack" |)
             ],
             make_dict []
           |),
@@ -105,7 +109,7 @@ Definition push : Value.t -> Value.t -> M :=
         |),
       (* then *)
       ltac:(M.monadic (
-        let _ := M.raise (| Some (M.get_name (| globals, "StackOverflowError" |)) |) in
+        let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "StackOverflowError" |)) |) in
         M.pure Constant.None_
       (* else *)
       )), ltac:(M.monadic (
@@ -113,9 +117,9 @@ Definition push : Value.t -> Value.t -> M :=
       )) |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "stack" |), "append" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "stack" |), "append" |),
         make_list [
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         ],
         make_dict []
       |)
diff --git a/CoqOfPython/ethereum/trace.v b/CoqOfPython/ethereum/trace.v
index c659277..35d4510 100644
--- a/CoqOfPython/ethereum/trace.v
+++ b/CoqOfPython/ethereum/trace.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.trace".
+Definition globals : Globals.t := "ethereum.trace".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -121,14 +123,15 @@ Definition GasAndRefund : Value.t :=
 
 Definition TraceEvent : Value.t := M.run ltac:(M.monadic (
   M.get_subscript (|
-    M.get_name (| globals, "Union" |),
-    make_tuple [ M.get_name (| globals, "TransactionStart" |); M.get_name (| globals, "TransactionEnd" |); M.get_name (| globals, "PrecompileStart" |); M.get_name (| globals, "PrecompileEnd" |); M.get_name (| globals, "OpStart" |); M.get_name (| globals, "OpEnd" |); M.get_name (| globals, "OpException" |); M.get_name (| globals, "EvmStop" |); M.get_name (| globals, "GasAndRefund" |) ]
+    M.get_name (| globals, locals_stack, "Union" |),
+    make_tuple [ M.get_name (| globals, locals_stack, "TransactionStart" |); M.get_name (| globals, locals_stack, "TransactionEnd" |); M.get_name (| globals, locals_stack, "PrecompileStart" |); M.get_name (| globals, locals_stack, "PrecompileEnd" |); M.get_name (| globals, locals_stack, "OpStart" |); M.get_name (| globals, locals_stack, "OpEnd" |); M.get_name (| globals, locals_stack, "OpException" |); M.get_name (| globals, locals_stack, "EvmStop" |); M.get_name (| globals, locals_stack, "GasAndRefund" |) ]
   |)
 )).
 
 Definition evm_trace : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "evm"; "event"; "trace_memory"; "trace_stack"; "trace_return_data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "evm"; "event"; "trace_memory"; "trace_stack"; "trace_return_data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Create a trace of the event.
     " in
diff --git a/CoqOfPython/ethereum/utils/__init__.v b/CoqOfPython/ethereum/utils/__init__.v
index aa7d70b..06bbfea 100644
--- a/CoqOfPython/ethereum/utils/__init__.v
+++ b/CoqOfPython/ethereum/utils/__init__.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.__init__".
+Definition globals : Globals.t := "ethereum.utils.__init__".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
diff --git a/CoqOfPython/ethereum/utils/byte.v b/CoqOfPython/ethereum/utils/byte.v
index 07efce7..6f96c51 100644
--- a/CoqOfPython/ethereum/utils/byte.v
+++ b/CoqOfPython/ethereum/utils/byte.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.byte".
+Definition globals : Globals.t := "ethereum.utils.byte".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -21,8 +23,9 @@ Axiom ethereum_base_types_imports_Bytes :
   IsImported globals "ethereum.base_types" "Bytes".
 
 Definition left_pad_zero_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Left pad zeroes to `value` if it's length is less than the given `size`.
 
@@ -40,9 +43,9 @@ Definition left_pad_zero_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "value" |), "rjust" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "value" |), "rjust" |),
         make_list [
-          M.get_name (| globals, "size" |);
+          M.get_name (| globals, locals_stack, "size" |);
           Constant.bytes "00"
         ],
         make_dict []
@@ -51,8 +54,9 @@ Definition left_pad_zero_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition right_pad_zero_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "size" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "size" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Right pad zeroes to `value` if it's length is less than the given `size`.
 
@@ -70,9 +74,9 @@ Definition right_pad_zero_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "value" |), "ljust" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "value" |), "ljust" |),
         make_list [
-          M.get_name (| globals, "size" |);
+          M.get_name (| globals, locals_stack, "size" |);
           Constant.bytes "00"
         ],
         make_dict []
diff --git a/CoqOfPython/ethereum/utils/ensure.v b/CoqOfPython/ethereum/utils/ensure.v
index 88c6e02..23f1393 100644
--- a/CoqOfPython/ethereum/utils/ensure.v
+++ b/CoqOfPython/ethereum/utils/ensure.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.ensure".
+Definition globals : Globals.t := "ethereum.utils.ensure".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -23,8 +25,9 @@ Axiom typing_imports_Union :
   IsImported globals "typing" "Union".
 
 Definition ensure : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value"; "exception" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value"; "exception" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Does nothing if `value` is truthy, otherwise raises the exception returned
     by `exception_class`.
@@ -41,7 +44,7 @@ Definition ensure : Value.t -> Value.t -> M :=
     let _ :=
       (* if *)
       M.if_then_else (|
-        M.get_name (| globals, "value" |),
+        M.get_name (| globals, locals_stack, "value" |),
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
@@ -52,5 +55,5 @@ Definition ensure : Value.t -> Value.t -> M :=
       )), ltac:(M.monadic (
         M.pure Constant.None_
       )) |) in
-    let _ := M.raise (| Some (M.get_name (| globals, "exception" |)) |) in
+    let _ := M.raise (| Some (M.get_name (| globals, locals_stack, "exception" |)) |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/utils/hexadecimal.v b/CoqOfPython/ethereum/utils/hexadecimal.v
index 822bc50..755d10a 100644
--- a/CoqOfPython/ethereum/utils/hexadecimal.v
+++ b/CoqOfPython/ethereum/utils/hexadecimal.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.hexadecimal".
+Definition globals : Globals.t := "ethereum.utils.hexadecimal".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -38,8 +40,9 @@ Axiom ethereum_crypto_hash_imports_Hash32 :
   IsImported globals "ethereum.crypto.hash" "Hash32".
 
 Definition has_hex_prefix : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Check if a hex string starts with hex prefix (0x).
 
@@ -55,7 +58,7 @@ Definition has_hex_prefix : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "hex_string" |), "startswith" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "hex_string" |), "startswith" |),
         make_list [
           Constant.str "0x"
         ],
@@ -65,8 +68,9 @@ Definition has_hex_prefix : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition remove_hex_prefix : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Remove 0x prefix from a hex string if present. This function returns the
     passed hex string if it isn't prefixed with 0x.
@@ -85,9 +89,9 @@ Definition remove_hex_prefix : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         M.call (|
-          M.get_name (| globals, "has_hex_prefix" |),
+          M.get_name (| globals, locals_stack, "has_hex_prefix" |),
           make_list [
-            M.get_name (| globals, "hex_string" |)
+            M.get_name (| globals, locals_stack, "hex_string" |)
           ],
           make_dict []
         |),
@@ -95,9 +99,9 @@ Definition remove_hex_prefix : Value.t -> Value.t -> M :=
       ltac:(M.monadic (
         let _ := M.return_ (|
           M.slice (|
-            M.get_name (| globals, "hex_string" |),
+            M.get_name (| globals, locals_stack, "hex_string" |),
             M.call (|
-              M.get_name (| globals, "len" |),
+              M.get_name (| globals, locals_stack, "len" |),
               make_list [
                 Constant.str "0x"
               ],
@@ -113,13 +117,14 @@ Definition remove_hex_prefix : Value.t -> Value.t -> M :=
         M.pure Constant.None_
       )) |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "hex_string" |)
+      M.get_name (| globals, locals_stack, "hex_string" |)
     |) in
     M.pure Constant.None_)).
 
 Definition hex_to_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to bytes.
 
@@ -135,12 +140,12 @@ Definition hex_to_bytes : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "remove_hex_prefix" |),
+            M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
             make_list [
-              M.get_name (| globals, "hex_string" |)
+              M.get_name (| globals, locals_stack, "hex_string" |)
             ],
             make_dict []
           |)
@@ -151,8 +156,9 @@ Definition hex_to_bytes : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bytes8 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to 8 bytes.
 
@@ -168,16 +174,16 @@ Definition hex_to_bytes8 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes8" |),
+        M.get_name (| globals, locals_stack, "Bytes8" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
@@ -197,8 +203,9 @@ Definition hex_to_bytes8 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bytes20 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to 20 bytes.
 
@@ -214,16 +221,16 @@ Definition hex_to_bytes20 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes20" |),
+        M.get_name (| globals, locals_stack, "Bytes20" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
@@ -243,8 +250,9 @@ Definition hex_to_bytes20 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bytes32 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to 32 bytes.
 
@@ -260,16 +268,16 @@ Definition hex_to_bytes32 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes32" |),
+        M.get_name (| globals, locals_stack, "Bytes32" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
@@ -289,8 +297,9 @@ Definition hex_to_bytes32 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_bytes256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to 256 bytes.
 
@@ -306,16 +315,16 @@ Definition hex_to_bytes256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Bytes256" |),
+        M.get_name (| globals, locals_stack, "Bytes256" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
                 M.get_field (| M.call (|
-                  M.get_name (| globals, "remove_hex_prefix" |),
+                  M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                   make_list [
-                    M.get_name (| globals, "hex_string" |)
+                    M.get_name (| globals, locals_stack, "hex_string" |)
                   ],
                   make_dict []
                 |), "rjust" |),
@@ -335,8 +344,9 @@ Definition hex_to_bytes256 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_hash : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to hash32 (32 bytes).
 
@@ -352,15 +362,15 @@ Definition hex_to_hash : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Hash32" |),
+        M.get_name (| globals, locals_stack, "Hash32" |),
         make_list [
           M.call (|
-            M.get_field (| M.get_name (| globals, "bytes" |), "fromhex" |),
+            M.get_field (| M.get_name (| globals, locals_stack, "bytes" |), "fromhex" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |)
@@ -374,8 +384,9 @@ Definition hex_to_hash : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_uint : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to Uint.
 
@@ -391,15 +402,15 @@ Definition hex_to_uint : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |);
@@ -414,8 +425,9 @@ Definition hex_to_uint : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_u64 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to U64.
 
@@ -431,15 +443,15 @@ Definition hex_to_u64 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "U64" |),
+        M.get_name (| globals, locals_stack, "U64" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |);
@@ -454,8 +466,9 @@ Definition hex_to_u64 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition hex_to_u256 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "hex_string" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "hex_string" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert hex string to U256.
 
@@ -471,15 +484,15 @@ Definition hex_to_u256 : Value.t -> Value.t -> M :=
     " in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "U256" |),
+        M.get_name (| globals, locals_stack, "U256" |),
         make_list [
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
               M.call (|
-                M.get_name (| globals, "remove_hex_prefix" |),
+                M.get_name (| globals, locals_stack, "remove_hex_prefix" |),
                 make_list [
-                  M.get_name (| globals, "hex_string" |)
+                  M.get_name (| globals, locals_stack, "hex_string" |)
                 ],
                 make_dict []
               |);
diff --git a/CoqOfPython/ethereum/utils/numeric.v b/CoqOfPython/ethereum/utils/numeric.v
index a3fc348..d616a17 100644
--- a/CoqOfPython/ethereum/utils/numeric.v
+++ b/CoqOfPython/ethereum/utils/numeric.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.numeric".
+Definition globals : Globals.t := "ethereum.utils.numeric".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -28,8 +30,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition get_sign : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Determines the sign of a number.
 
@@ -48,7 +51,7 @@ Definition get_sign : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt (|
-          M.get_name (| globals, "value" |),
+          M.get_name (| globals, locals_stack, "value" |),
           Constant.int 0
         |),
       (* then *)
@@ -63,7 +66,7 @@ Definition get_sign : Value.t -> Value.t -> M :=
           (* if *)
           M.if_then_else (|
             Compare.eq (|
-              M.get_name (| globals, "value" |),
+              M.get_name (| globals, locals_stack, "value" |),
               Constant.int 0
             |),
           (* then *)
@@ -84,8 +87,9 @@ Definition get_sign : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition ceil32 : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "value" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "value" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Converts a unsigned integer to the next closest multiple of 32.
 
@@ -104,7 +108,7 @@ Definition ceil32 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "ceiling" ,
       M.call (|
-        M.get_name (| globals, "Uint" |),
+        M.get_name (| globals, locals_stack, "Uint" |),
         make_list [
           Constant.int 32
         ],
@@ -114,17 +118,17 @@ Definition ceil32 : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "remainder" ,
       BinOp.mod_ (|
-        M.get_name (| globals, "value" |),
-        M.get_name (| globals, "ceiling" |)
+        M.get_name (| globals, locals_stack, "value" |),
+        M.get_name (| globals, locals_stack, "ceiling" |)
       |)
     |) in
     let _ :=
       (* if *)
       M.if_then_else (|
         Compare.eq (|
-          M.get_name (| globals, "remainder" |),
+          M.get_name (| globals, locals_stack, "remainder" |),
           M.call (|
-            M.get_name (| globals, "Uint" |),
+            M.get_name (| globals, locals_stack, "Uint" |),
             make_list [
               Constant.int 0
             ],
@@ -134,7 +138,7 @@ Definition ceil32 : Value.t -> Value.t -> M :=
       (* then *)
       ltac:(M.monadic (
         let _ := M.return_ (|
-          M.get_name (| globals, "value" |)
+          M.get_name (| globals, locals_stack, "value" |)
         |) in
         M.pure Constant.None_
       (* else *)
@@ -142,10 +146,10 @@ Definition ceil32 : Value.t -> Value.t -> M :=
         let _ := M.return_ (|
           BinOp.sub (|
             BinOp.add (|
-              M.get_name (| globals, "value" |),
-              M.get_name (| globals, "ceiling" |)
+              M.get_name (| globals, locals_stack, "value" |),
+              M.get_name (| globals, locals_stack, "ceiling" |)
             |),
-            M.get_name (| globals, "remainder" |)
+            M.get_name (| globals, locals_stack, "remainder" |)
           |)
         |) in
         M.pure Constant.None_
@@ -153,8 +157,9 @@ Definition ceil32 : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition is_prime : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "number" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "number" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Checks if `number` is a prime number.
 
@@ -172,7 +177,7 @@ Definition is_prime : Value.t -> Value.t -> M :=
       (* if *)
       M.if_then_else (|
         Compare.lt_e (|
-          M.get_name (| globals, "number" |),
+          M.get_name (| globals, locals_stack, "number" |),
           Constant.int 1
         |),
       (* then *)
@@ -187,17 +192,17 @@ Definition is_prime : Value.t -> Value.t -> M :=
       )) |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "x" |),
+        M.get_name (| globals, locals_stack, "x" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 2;
         BinOp.add (|
           M.call (|
-            M.get_name (| globals, "int" |),
+            M.get_name (| globals, locals_stack, "int" |),
             make_list [
               BinOp.pow (|
-                M.get_name (| globals, "number" |),
+                M.get_name (| globals, locals_stack, "number" |),
                 Constant.float "0.5"
               |)
             ],
@@ -214,8 +219,8 @@ Definition is_prime : Value.t -> Value.t -> M :=
             M.if_then_else (|
               Compare.eq (|
                 BinOp.mod_ (|
-                  M.get_name (| globals, "number" |),
-                  M.get_name (| globals, "x" |)
+                  M.get_name (| globals, locals_stack, "number" |),
+                  M.get_name (| globals, locals_stack, "x" |)
                 |),
                 Constant.int 0
               |),
@@ -241,8 +246,9 @@ Definition is_prime : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition le_bytes_to_uint32_sequence : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "data" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "data" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Convert little endian byte stream `data` to a little endian U32
     sequence i.e., the first U32 number of the sequence is the least
@@ -266,15 +272,15 @@ Definition le_bytes_to_uint32_sequence : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "i" |),
+        M.get_name (| globals, locals_stack, "i" |),
         M.call (|
-      M.get_name (| globals, "range" |),
+      M.get_name (| globals, locals_stack, "range" |),
       make_list [
         Constant.int 0;
         M.call (|
-          M.get_name (| globals, "len" |),
+          M.get_name (| globals, locals_stack, "len" |),
           make_list [
-            M.get_name (| globals, "data" |)
+            M.get_name (| globals, locals_stack, "data" |)
           ],
           make_dict []
         |);
@@ -284,16 +290,16 @@ Definition le_bytes_to_uint32_sequence : Value.t -> Value.t -> M :=
     |),
         ltac:(M.monadic (
           let _ := M.call (|
-    M.get_field (| M.get_name (| globals, "sequence" |), "append" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "sequence" |), "append" |),
     make_list [
       M.call (|
-        M.get_field (| M.get_name (| globals, "U32" |), "from_le_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "U32" |), "from_le_bytes" |),
         make_list [
           M.slice (|
-            M.get_name (| globals, "data" |),
-            M.get_name (| globals, "i" |),
+            M.get_name (| globals, locals_stack, "data" |),
+            M.get_name (| globals, locals_stack, "i" |),
             BinOp.add (|
-              M.get_name (| globals, "i" |),
+              M.get_name (| globals, locals_stack, "i" |),
               Constant.int 4
             |),
             Constant.None_
@@ -312,9 +318,9 @@ Definition le_bytes_to_uint32_sequence : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_name (| globals, "tuple" |),
+        M.get_name (| globals, locals_stack, "tuple" |),
         make_list [
-          M.get_name (| globals, "sequence" |)
+          M.get_name (| globals, locals_stack, "sequence" |)
         ],
         make_dict []
       |)
@@ -322,8 +328,9 @@ Definition le_bytes_to_uint32_sequence : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition le_uint32_sequence_to_bytes : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "sequence" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "sequence" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain little endian byte stream from a little endian U32 sequence
     i.e., the first U32 number of the sequence is the least significant
@@ -354,14 +361,14 @@ Definition le_uint32_sequence_to_bytes : Value.t -> Value.t -> M :=
     |) in
     let _ :=
       M.for_ (|
-        M.get_name (| globals, "item" |),
-        M.get_name (| globals, "sequence" |),
+        M.get_name (| globals, locals_stack, "item" |),
+        M.get_name (| globals, locals_stack, "sequence" |),
         ltac:(M.monadic (
           let _ := M.assign_op_local (|
             BinOp.add,
             "result_bytes",
             M.call (|
-    M.get_field (| M.get_name (| globals, "item" |), "to_le_bytes4" |),
+    M.get_field (| M.get_name (| globals, locals_stack, "item" |), "to_le_bytes4" |),
     make_list [],
     make_dict []
   |)
@@ -373,13 +380,14 @@ Definition le_uint32_sequence_to_bytes : Value.t -> Value.t -> M :=
         ))
     |) in
     let _ := M.return_ (|
-      M.get_name (| globals, "result_bytes" |)
+      M.get_name (| globals, locals_stack, "result_bytes" |)
     |) in
     M.pure Constant.None_)).
 
 Definition le_uint32_sequence_to_uint : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "sequence" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "sequence" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Obtain Uint from a U32 sequence assuming that this sequence is little
     endian i.e., the first U32 number of the sequence is the least
@@ -399,18 +407,18 @@ Definition le_uint32_sequence_to_uint : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "sequence_as_bytes" ,
       M.call (|
-        M.get_name (| globals, "le_uint32_sequence_to_bytes" |),
+        M.get_name (| globals, locals_stack, "le_uint32_sequence_to_bytes" |),
         make_list [
-          M.get_name (| globals, "sequence" |)
+          M.get_name (| globals, locals_stack, "sequence" |)
         ],
         make_dict []
       |)
     |) in
     let _ := M.return_ (|
       M.call (|
-        M.get_field (| M.get_name (| globals, "Uint" |), "from_le_bytes" |),
+        M.get_field (| M.get_name (| globals, locals_stack, "Uint" |), "from_le_bytes" |),
         make_list [
-          M.get_name (| globals, "sequence_as_bytes" |)
+          M.get_name (| globals, locals_stack, "sequence_as_bytes" |)
         ],
         make_dict []
       |)
@@ -418,8 +426,9 @@ Definition le_uint32_sequence_to_uint : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition taylor_exponential : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [ "factor"; "numerator"; "denominator" ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [ "factor"; "numerator"; "denominator" ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Approximates factor * e ** (numerator / denominator) using
     Taylor expansion.
@@ -450,32 +459,32 @@ Definition taylor_exponential : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "numerator_accumulated" ,
       BinOp.mult (|
-        M.get_name (| globals, "factor" |),
-        M.get_name (| globals, "denominator" |)
+        M.get_name (| globals, locals_stack, "factor" |),
+        M.get_name (| globals, locals_stack, "denominator" |)
       |)
     |) in
     let _ :=
       M.while (|
         Compare.gt (|
-      M.get_name (| globals, "numerator_accumulated" |),
+      M.get_name (| globals, locals_stack, "numerator_accumulated" |),
       Constant.int 0
     |),
         ltac:(M.monadic (
           let _ := M.assign_op_local (|
             BinOp.add,
             "output",
-            M.get_name (| globals, "numerator_accumulated" |)
+            M.get_name (| globals, locals_stack, "numerator_accumulated" |)
           |) in
           let _ := M.assign_local (|
             "numerator_accumulated" ,
             BinOp.floor_div (|
               BinOp.mult (|
-                M.get_name (| globals, "numerator_accumulated" |),
-                M.get_name (| globals, "numerator" |)
+                M.get_name (| globals, locals_stack, "numerator_accumulated" |),
+                M.get_name (| globals, locals_stack, "numerator" |)
               |),
               BinOp.mult (|
-                M.get_name (| globals, "denominator" |),
-                M.get_name (| globals, "i" |)
+                M.get_name (| globals, locals_stack, "denominator" |),
+                M.get_name (| globals, locals_stack, "i" |)
               |)
             |)
           |) in
@@ -492,8 +501,8 @@ Definition taylor_exponential : Value.t -> Value.t -> M :=
     |) in
     let _ := M.return_ (|
       BinOp.floor_div (|
-        M.get_name (| globals, "output" |),
-        M.get_name (| globals, "denominator" |)
+        M.get_name (| globals, locals_stack, "output" |),
+        M.get_name (| globals, locals_stack, "denominator" |)
       |)
     |) in
     M.pure Constant.None_)).
diff --git a/CoqOfPython/ethereum/utils/safe_arithmetic.v b/CoqOfPython/ethereum/utils/safe_arithmetic.v
index 0702f0e..3134fee 100644
--- a/CoqOfPython/ethereum/utils/safe_arithmetic.v
+++ b/CoqOfPython/ethereum/utils/safe_arithmetic.v
@@ -1,6 +1,8 @@
 Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "ethereum.utils.safe_arithmetic".
+Definition globals : Globals.t := "ethereum.utils.safe_arithmetic".
+
+Definition locals_stack : list Locals.t := [].
 
 Definition expr_1 : Value.t :=
   Constant.str "
@@ -30,8 +32,9 @@ Axiom ethereum_base_types_imports_Uint :
   IsImported globals "ethereum.base_types" "Uint".
 
 Definition u256_safe_add : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [  ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [  ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Adds together the given sequence of numbers. If the total sum of the
     numbers exceeds `U256.MAX_VALUE` then an exception is raised.
@@ -61,8 +64,9 @@ Definition u256_safe_add : Value.t -> Value.t -> M :=
     M.pure Constant.None_)).
 
 Definition u256_safe_multiply : Value.t -> Value.t -> M :=
-  fun (args kwargs : Value.t) => ltac:(M.monadic (
-    let _ := M.set_locals (| args, kwargs, [  ] |) in
+  fun (args kwargs : Value.t) =>
+    let- locals_stack := M.create_locals locals_stack args kwargs [  ] in
+    ltac:(M.monadic (
     let _ := Constant.str "
     Multiplies together the given sequence of numbers. If the net product of
     the numbers exceeds `U256.MAX_VALUE` then an exception is raised.
@@ -91,7 +95,7 @@ Definition u256_safe_multiply : Value.t -> Value.t -> M :=
     let _ := M.assign_local (|
       "result" ,
       M.get_subscript (|
-        M.get_name (| globals, "numbers" |),
+        M.get_name (| globals, locals_stack, "numbers" |),
         Constant.int 0
       |)
     |) in
diff --git a/CoqOfPython/proofs/CoqOfPython.v b/CoqOfPython/proofs/CoqOfPython.v
new file mode 100644
index 0000000..474a8f2
--- /dev/null
+++ b/CoqOfPython/proofs/CoqOfPython.v
@@ -0,0 +1,214 @@
+Require Import CoqOfPython.CoqOfPython.
+
+Module Stack.
+  Definition t : Set :=
+    list {A : Set @ A}.
+
+  Definition read : t -> nat -> option {A : Set @ A} :=
+    List.nth_error (A := {A : Set @ A}).
+
+  Fixpoint write {A : Set} (stack : t) (index : nat) (value : A) : t :=
+    match stack, index with
+    | start :: stack, Datatypes.O => (existS A value) :: stack
+    | start :: stack, Datatypes.S index => start :: write stack index value
+    | [], _ => []
+    end.
+
+  Lemma read_length_eq {A : Set} (stack_start stack_end : t) :
+    read (stack_start ++ stack_end) (List.length stack_start) =
+    read stack_end 0.
+  Proof.
+    now induction stack_start.
+  Qed.
+End Stack.
+
+(** The precise type of the heap is provided by the user. We only enforce some consistency
+    properties between the read and write operations. *)
+Module Heap.
+  Class Trait (Heap Address : Set) : Type := {
+    get_Set (a : Address) : Set;
+    read (a : Address) : Heap -> option (get_Set a);
+    alloc_write (a : Address) : Heap -> get_Set a -> option Heap;
+  }.
+
+  Module Valid.
+    (** A valid heap should behave as map from address to optional values
+        of the type given by the address. A value is [None] while not
+        allocated, and [Some] once allocated. It is impossible to free
+        allocated values. *)
+    Record t `(Trait) : Prop := {
+      (* [alloc_write] can only fail on new cells *)
+      not_allocated (a : Address) (h : Heap) (v : get_Set a) :
+        match alloc_write a h v with
+        | Some _ => True
+        | None => read a h = None
+        end;
+      same (a : Address) (h : Heap) (v : get_Set a) :
+        match alloc_write a h v with
+        | Some h => read a h = Some v
+        | None => True
+        end;
+      different (a1 a2 : Address) (h : Heap) (v2 : get_Set a2) :
+        a1 <> a2 ->
+        match alloc_write a2 h v2 with
+        | Some h' => read a1 h' = read a1 h
+        | None => True
+        end;
+        }.
+  End Valid.
+End Heap.
+
+Module Run.
+  Reserved Notation "{{ stack , heap | e ⇓ result | stack' , heap' }}".
+
+  Inductive t `{Heap.Trait} {A : Set}
+      (* Be aware of the order of parameters: the result and final heap are at
+         the beginning. This is due to the way polymorphic types for inductive
+         work in Coq, and the fact that the result is always the same as we are
+         in continuation passing style. *)
+      {result : A} {stack' : Stack.t} {heap' : Heap} :
+      LowM.t A -> Stack.t -> Heap -> Prop :=
+  | Pure :
+    {{ stack', heap' |
+      LowM.Pure result ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateAllocImmediate
+      (stack : Stack.t) (heap : Heap) (object : Object.t Value.t)
+      (k : Pointer.t Value.t -> LowM.t A) :
+    {{ stack, heap |
+      k (Pointer.Imm object) ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateAlloc object) k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateAllocStack {B : Set}
+      (value : B)
+      (to_object : B -> Object.t Value.t)
+      (object : Object.t Value.t)
+      (stack : Stack.t) (heap : Heap)
+      (k : Pointer.t Value.t -> LowM.t A) :
+    let stack_inter := (stack ++ [existS B value])%list in
+    let index := List.length stack in
+    let mutable := Pointer.Mutable.Stack index to_object in
+    object = to_object value ->
+    {{ stack_inter, heap |
+      k (Pointer.Mutable mutable) ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateAlloc object) k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateAllocHeap
+      (address : Address)
+      (value : Heap.get_Set address)
+      (object : Object.t Value.t)
+      (to_object : Heap.get_Set address -> Object.t Value.t)
+      (stack : Stack.t) (heap heap_inter : Heap)
+      (k : Pointer.t Value.t -> LowM.t A) :
+    let mutable := Pointer.Mutable.Heap address to_object in
+    object = to_object value ->
+    Heap.read address heap = None ->
+    Heap.alloc_write address heap value = Some heap_inter ->
+    {{ stack, heap_inter |
+      k (Pointer.Mutable mutable) ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateAlloc object) k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateReadStack {B : Set}
+      (index : nat)
+      (to_object : B -> Object.t Value.t)
+      (value : B)
+      (stack : Stack.t) (heap : Heap)
+      (k : Object.t Value.t -> LowM.t A) :
+    let mutable := Pointer.Mutable.Stack index to_object in
+    Stack.read stack index = Some (existS B value) ->
+    {{ stack, heap |
+      k (to_object value) ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateRead mutable) k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateReadHeap
+      (address : Address)
+      (to_object : Heap.get_Set address -> Object.t Value.t)
+      (value : Heap.get_Set address)
+      (stack : Stack.t) (heap : Heap)
+      (k : Object.t Value.t -> LowM.t A) :
+    let mutable := Pointer.Mutable.Heap address to_object in
+    Heap.read address heap = Some value ->
+    {{ stack, heap |
+      k (to_object value) ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateRead mutable) k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateWriteStack {B : Set}
+      (index : nat)
+      (to_object : B -> Object.t Value.t)
+      (update : B)
+      (update' : Object.t Value.t)
+      (stack : Stack.t) (heap : Heap)
+      (k : unit -> LowM.t A) :
+    let stack_inter := Stack.write stack index update in
+    let mutable := Pointer.Mutable.Stack index to_object in
+    update' = to_object update ->
+    {{ stack_inter, heap |
+      k tt ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateWrite mutable update') k ⇓
+      result
+    | stack', heap' }}
+  | CallPrimitiveStateWriteHeap
+      (address : Address)
+      (to_object : Heap.get_Set address -> Object.t Value.t)
+      (update : Heap.get_Set address)
+      (update' : Object.t Value.t)
+      (stack : Stack.t) (heap heap_inter : Heap)
+      (k : unit -> LowM.t A) :
+    let mutable := Pointer.Mutable.Heap address to_object in
+    update' = to_object update ->
+    Heap.alloc_write address heap update = Some heap_inter ->
+    {{ stack, heap_inter |
+      k tt ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallPrimitive (Primitive.StateWrite mutable update') k ⇓
+      result
+    | stack', heap' }}
+  | CallClosure
+      (stack stack_inter : Stack.t) (heap heap_inter : Heap)
+      (f : Value.t -> Value.t -> M)
+      (args kwargs : Value.t)
+      (value : Value.t + Exception.t)
+      (k : Value.t + Exception.t -> LowM.t A) :
+    let closure := Data.Closure f in
+    {{ stack, heap |
+      f args kwargs ⇓
+      value
+    | stack_inter, heap_inter }} ->
+    {{ stack_inter, heap_inter |
+      k value ⇓
+      result
+    | stack', heap' }} ->
+    {{ stack, heap |
+      LowM.CallClosure closure args kwargs k ⇓
+      result
+    | stack', heap' }}
+
+  where "{{ stack , heap | e ⇓ result | stack' , heap' }}" :=
+    (t (result := result) (stack' := stack') (heap' := heap') e stack heap).
+End Run.
diff --git a/CoqOfPython/proofs/heap.v b/CoqOfPython/proofs/heap.v
new file mode 100644
index 0000000..5d336c0
--- /dev/null
+++ b/CoqOfPython/proofs/heap.v
@@ -0,0 +1,37 @@
+(** * The memory that we use to interpret the translated Python code. *)
+Require Import CoqOfPython.CoqOfPython.
+Require Import proofs.CoqOfPython.
+
+Require ethereum.paris.vm.simulations.__init__.
+Module Evm := __init__.Evm.
+
+Module Address.
+  Inductive t : Set :=
+  | Evm.
+End Address.
+
+Module Heap.
+  Record t : Set := {
+    evm : Evm.t;
+  }.
+
+  Global Instance I : Heap.Trait Heap.t Address.t := {
+    get_Set a :=
+      match a with
+      | Address.Evm => Evm.t
+      end;
+    read a h :=
+      match a with
+      | Address.Evm => Some h.(evm)
+      end;
+    alloc_write a h :=
+      match a with
+      | Address.Evm => fun v => Some (h <| evm := v |>)
+      end;
+  }.
+
+  Lemma is_valid : Heap.Valid.t I.
+  Proof.
+    sauto.
+  Qed.
+End Heap.
diff --git a/CoqOfPython/simulations/CoqOfPython.v b/CoqOfPython/simulations/CoqOfPython.v
new file mode 100644
index 0000000..004649c
--- /dev/null
+++ b/CoqOfPython/simulations/CoqOfPython.v
@@ -0,0 +1,94 @@
+Require Import CoqOfPython.CoqOfPython.
+
+Module Lens.
+  Record t {Big_A A : Set} : Set := {
+    read : Big_A -> A;
+    write : Big_A -> A -> Big_A
+  }.
+  Arguments t : clear implicits.
+End Lens.
+
+(** ** Monads that are useful for the definition of simulations. *)
+
+Module Error.
+  Definition t (Error A : Set) : Set := A + Error.
+
+  Definition return_ {Error A : Set} (value : A) : t Error A := inl value.
+
+  Definition bind {Error A B : Set} (value : t Error A) (f : A -> t Error B) : t Error B :=
+    match value with
+    | inl value => f value
+    | inr error => inr error
+    end.
+
+  Definition raise {Error A : Set} (error : Error) : t Error A := inr error.
+End Error.
+
+Module StateError.
+  Definition t (State Error A : Set) : Set := State -> (A + Error) * State.
+
+  Definition return_ {State Error A : Set} (value : A) : t State Error A :=
+    fun state => (inl value, state).
+
+  Definition bind {State Error A B : Set} (value : t State Error A) (f : A -> t State Error B) :
+      t State Error B :=
+    fun state =>
+      let (value, state) := value state in
+      match value with
+      | inl value => f value state
+      | inr error => (inr error, state)
+      end.
+
+  Definition read {State Error : Set} : t State Error State :=
+    fun state => (inl state, state).
+
+  Definition write {State Error : Set} (state : State) : t State Error unit :=
+    fun _ => (inl tt, state).
+
+  Definition raise {State Error A : Set} (msg : Error) : t State Error A :=
+    fun state => (inr msg, state).
+
+  Definition lift_from_error {State Error A : Set} (value : Error.t Error A) : t State Error A :=
+    fun state =>
+    (value, state).
+
+  Definition lift_lens {Big_State State Error A : Set}
+      (lens : Lens.t Big_State State)
+      (value : t State Error A) :
+      t Big_State Error A :=
+    fun big_state =>
+      let (value, state) := value (lens.(Lens.read) big_state) in
+      (value, lens.(Lens.write) big_state state).
+End StateError.
+
+Module Notations.
+  Notation "M?" := Error.t.
+
+  Notation "return?" := Error.return_.
+
+  Notation "'let?' x ':=' X 'in' Y" :=
+    (Error.bind X (fun x => Y))
+    (at level 200, x name, X at level 100, Y at level 200).
+
+  Notation "'let?' ' x ':=' X 'in' Y" :=
+    (Error.bind X (fun x => Y))
+    (at level 200, x pattern, X at level 100, Y at level 200).
+
+  Notation "MS?" := StateError.t.
+
+  Notation "returnS?" := StateError.return_.
+
+  Notation "'letS?' x ':=' X 'in' Y" :=
+    (StateError.bind X (fun x => Y))
+    (at level 200, x name, X at level 100, Y at level 200).
+
+  Notation "'letS?' ' x ':=' X 'in' Y" :=
+    (StateError.bind X (fun x => Y))
+    (at level 200, x pattern, X at level 100, Y at level 200).
+
+  Notation "readS?" := StateError.read.
+
+  Notation "writeS?" := StateError.write.
+
+  Notation "return?toS?" := StateError.lift_from_error.
+End Notations.
\ No newline at end of file
diff --git a/CoqOfPython/simulations/builtins.v b/CoqOfPython/simulations/builtins.v
new file mode 100644
index 0000000..cc29a8f
--- /dev/null
+++ b/CoqOfPython/simulations/builtins.v
@@ -0,0 +1,14 @@
+Require Import CoqOfPython.CoqOfPython.
+Require ethereum.simulations.exceptions.
+
+Module ArithmeticError.
+  Inductive t : Set :=
+  | OverflowError.
+End ArithmeticError.
+
+Module Exception.
+  (** Here we exhaustively desbribe which are the possible exceptions. *)
+  Inductive t : Set :=
+  | ArithmeticError (exn : ArithmeticError.t)
+  | EthereumException (exn : exceptions.EthereumException.t).
+End Exception.
diff --git a/convert_all.py b/convert_all.py
deleted file mode 100644
index 5e85864..0000000
--- a/convert_all.py
+++ /dev/null
@@ -1,26 +0,0 @@
-import os
-import subprocess
-import sys
-
-folder_to_convert = "../execution-specs/src/ethereum"
-
-# for each file recursively in the folder
-for root, dirs, files in os.walk(folder_to_convert):
-    for file in files:
-        if file.endswith(".py"):
-            # convert the file
-            full_path = root + "/" + file
-            short_path = full_path[(len(folder_to_convert) + 1):]
-            print("")
-            print("Converting file: " + short_path)
-
-            try:
-                command = "python main.py " + folder_to_convert + " " + short_path
-                print(command)
-                subprocess.run(command, shell=True, check=True)
-            except subprocess.CalledProcessError as e:
-                print(f"Error occurred: {e}")
-                sys.exit(1)
-            except KeyboardInterrupt:
-                print("Ctrl-C pressed, interrupting the script.")
-                sys.exit(1)
diff --git a/main.py b/main.py
index 332e894..f01ed25 100644
--- a/main.py
+++ b/main.py
@@ -197,9 +197,10 @@ def generate_function_def_body(indent, node):
     params = "; ".join(f"\"{arg.arg}\"" for arg in node.args.args)
     body = generate_stmts(indent + 1, node.body)
 
-    return "fun (args kwargs : Value.t) => ltac:(M.monadic (\n" + \
+    return "fun (args kwargs : Value.t) =>\n" + \
         generate_indent(indent + 1) + \
-        f"let _ := M.set_locals (| args, kwargs, [ {params} ] |) in\n" + \
+        f"let- locals_stack := M.create_locals locals_stack args kwargs [ {params} ] in\n" + \
+        generate_indent(indent + 1) + "ltac:(M.monadic (\n" + \
         body + "))"
 
 
@@ -602,7 +603,7 @@ def generate_expr(indent, is_with_paren, node: ast.expr):
     elif isinstance(node, ast.Name):
         return paren(
             is_with_paren,
-            f"M.get_name (| globals, \"{node.id}\" |)"
+            f"M.get_name (| globals, locals_stack, \"{node.id}\" |)"
         )
     elif isinstance(node, ast.List):
         return generate_list(indent, is_with_paren, node.elts)
@@ -715,7 +716,7 @@ def generate_arg(node):
 
 
 input_file_name = sys.argv[1]
-output_file_name = "../../translate-ethereum-specs/CoqOfPython/" + \
+output_file_name = "../../coq-of-python/CoqOfPython/" + \
     input_file_name.replace(".py", ".v")
 
 file_content = open(input_file_name).read()
@@ -726,7 +727,9 @@ def generate_arg(node):
 # Generate Coq code from the AST
 coq_code = f"""Require Import CoqOfPython.CoqOfPython.
 
-Definition globals : string := "{globals}".
+Definition globals : Globals.t := "{globals}".
+
+Definition locals_stack : list Locals.t := [].
 
 {generate_mod(parsed_tree)}
 """